6th or 7th generation is the furthest that I have been able to get in TS3 without the game/save file utterly breaking or the town feeling critically inbreed.

I've actually been playing with the same extended family since the game was first released.back in 2009. My current Sim family is descended from that original Sim family. However, I don't keep them in the same neighborhood and have started many new save games with them, so I'm not sure if it counts as a legacy family. I usually switch neighborhoods when I get bored, a new world comes out, and/or my current save is getting too big.

I think the longest I've played a family in the same neighborhood and same save game is third or fourth generation.

I'm approaching third generation with my current playthrough, which is...impressive for me, to say the least. I'm doing a Random Legacy thing with it, I think that's what's keeping me invested.

Third generation. I always set out to make epic legacys, but I have a very short attentionspan. :c

Longest ever for me, I'm currently on generation 17, week 180. I'm playing in a small town on normal lifespan, but a few of them have been vampires and fairies, so longer lifespans for them. I'd never made it past gen 5 or 6 before and even that was a stretch. I can't believe it's going this long, I've been playing it for about 2 months now. I hadn't been able to play a save more than a few (real life) weeks for about 2 years. I think switching to a small world made the difference.

Seems like every time I get to a third generation my game glitches and I have to start over. What a shame. But thumbs up to those that lasted 14 generations.

Elledee, 17 generations in 2 months?! You leave the game on while you're sleeping?
I'm currently on 15, five of them I made in one savegame in Lucky Palms, and this savegame is more then 2 GB now. Takes forever to save and load

Haha, yes I do play for long periods of time almost every day. I actually had taken a week off from playing too, lol. I don't normally play my towns like this either. I usually play long or epic lifespans and take my time. It all started when I was trying out some new worlds to play and I decided to stick with that one. I had no idea it was going to go on for as long as it did, so now I'm just trying to see how long I can keep it running before it breaks. There were quite a few times when I thought it had broke but I managed to fix the problems that came up and keep going. My save file is only 213MB, so it's not massive. It still only takes a couple of minutes to save. I think the reason it's run for so long is because it's a small world.

In Sims 3? Hmmm....generation 4 probably. My last legacy style family that I played was around generation 4 when my hard drive died. Now my current family is on generation 2 but I plan to work on generation 3 tonight since my gen 2 heir is newly married. I plan to play this family long term, assuming nothing weird happens in my game or with my PC.

In Sims 2 the highest I ever got was generation 8 and then my PC crashed and burned. I still miss that family sometimes even though it's been at least 5 years since that happened. I have a new PC so I hope it'll be a very long time before anything like that happens again. I should get better about storing game backups on an external hard drive.

I haven't played through families long enough to go past the kid having part, but in sims 2, my longest tends to be around the fifth generation. I seemed to be cursed with the fifth one as something always happens that causes me to lose the family and I have to start over.

Currently, I trying something different with sims 3. Now that I have seasons, I'm going to age my sims only 1 day out of the entire year. On the first day of spring, I will turn aging back on to let them add another day then turn it off the rest of the year. It bothers me that a sim can become an elder within the first year of his life. I want my sims to enjoy all seasons at all stages of life. And I also want to experience much in the game. Skilling takes too much time for any life span. I suppose in a way I'm simultaneously making my game both much harder and much easier. After all, I am going to have to put up with babies and toddlers for 8 seasons a piece.

TS2, 13 generations. I got bored with them and felt like I needed a change.
TS3, am currently on Generation 7. It's my *knocks on wood* longest family yet.

I once made it to a third generation, but usually I'm too attached to my sims to let them die or I get bored of the game before the second generation has a chance to get past the child stage. This thread has inspired me to try and keep a family for as many generations as possible though. I'm only at generation two right now so we'll see how this goes.

So, forgive me if this is a dumb question: to those of you who have 5+ generations, does simply "saving as" a different file name prevent heavy save files and game glitches, or do you have to move your sim to the bin and restart in a freshly made game? Or is there some other secret? I have trouble getting even to the middle of the 3rd generation before things go kaput and my game starts freezing every couple of minutes.

I don't have more than a few save files for mine. I have had bugs where it didn't save. I clicked "Save As" and it was stuck in a loop and didn't save the file. In those cases I had to exit through the task manager. There were a few times when I had some strange glitches, like the sound would cut out and then some time later all the sounds would play at once, but that was a long time ago, somewhere around generation 6-8 (I can't remember). I was getting a lot of error 16s back then. I thought my town was glitching on its way out and I was truly surprised when it kept going. I clean the caches and run save cleaner regularly. I keep the population down. I haven't had any major issues or crash to desktops for the past month. I only recently added Nraas SP back in because things were getting boring and I had a few lag/crashes while looking in map view, so I just lowered the population a bit more and it seems fine. They have been in only one town since I started.

I also never was able to get very far, I don't know what happened this time, as I always cleaned the caches and ran save cleaner with my others as well. The major difference was the lifespans and size world I chose for this town.

This isn't dumb question at all, I know many people have problems with Sims 3. I wouldn't call it a secret, but I have some rules.
I do save through "save as..." option every time, although it doesn't prevent heavy save files (my current dynasty save is more than 2 GB). I do it to be able to go back and in case of save corruption.
I don't switch between families. Ever. In other savegames I do, but not in the long term legacy game.
I know this is risky thing to say on *Mod*thesims, but, well... I almost don't use mods, not in legacy game, only install them when I need some bug to fix and then delete them right away (Overwatch, MK). I do have glitches from time to time but they aren't so bad, just annoying, and none of them led to "kaput". It's like corrupted family tree and the like. Most bugs are from travelling, and here's where I need mods to clean up after EA.
I try not to use cheats too. And if need, I make it quick and turn them off straight away.
When I got to the point when I got bored and also there were many glitches in savegame, I moved my family to the bin and restarted in a new game, like you said. I managed to play 10 generations in Sunset Valley, before I decided to move, then I spent half of generation in Appaloosa, then Lucky Palms has been released and I liked it, so moved again. Now I'm on 15 (5) generation in Lucky Palms. In fact, this family survived about 3 complete game reinstallations and many add-ons, stuff packs and patches so far.
As for freezing, I found it VERY usefull to reduce amount of lots. Replaced some separate rabbitholes with merged ones, deleted a couple of useless parks and some ugly residential lots, combined consignment store, elixir store and World Adventures registers in one place, and so on. Now I haven't got any lag, except for CAS and CAST. Fan under the laptop also helps improve performance =)
The only problem lately is loading and saving time. There's that tutorial how to reduce the size of savegame files in Simpe, I did it once, but it's real pain in the ass to delete parts manually. You can delete the whole TravelDB.package, but since I don't want to lose in-game photos and paintings, that's not an option (I keeped some of them since the very first generation, no way I delete them!).

I echo keeping the amount of lots down, I have merged rabbitholes and bulldozed lots I don't use and replaced them with something else. I keep everything basic. The world I'm using is small, but it's got variety. I use mods and cheats and only added Nraas SP back in within the past week. I was afraid to add that back in because I know it causes lag, but it hasn't really caused me any problems. I do get a tiny bit of lag here and there with it, but nothing to worry about.

The glitches I had were save errors (16s or "saving" but not actually saving), some random crash to desktops, and the weird sound cuts followed by a huge stack of sounds playing at once, but I haven't seen those problems for about a month now.

If you don't have Save Cleaner, I recommend getting it. It reduces the amount of your save and gets rid of all the clutter. I think it basically does the same thing as people do manually to reduce their save files, but I'm not confident enough to touch those myself, so Save Cleaner does the job for me.

I think I have made it to the 5th or 6th generation with a family before. Think that was a few years ago though, honestly I think I have gone further with Sims 2 then 3.

Sadly now, it seems if I play that savefile for aleast two-three generations, my game starts going slower and doing that freeze every few sim minutes or hour, I will get to that eventually, just can't be bothered seeing what the problem is. Might just be I play on fast speed, especially if I am cheating to keep the motives up, so everything happens faster, more deaths and more generations (Damn eldery, especially zombies dying on my lot)

My current record and still ongoing legacy is 7 generations, my save is a bit over a month old. Let me just say that the town is getting hideous. I tempted to kill them all off and replace them with my own sims, they make all the premades look like models.

I have the attention span of a fish, but I think I might've gotten to gen 5 once? But that was only because I was playing with a town populated only with my own sims and I hopped from household to household.

I'm currently on Generation 4, and that's the highest I've gotten to. For me, it's not the question of attention span, it's my impatience and the fact that I get bored easily. If I told you how many times I have tried to start a legacy... I can't play Pinstar's version, where you have to be a hobo, I have to play with a house. If not, I'll never have the funds/need to build a house.

Waiting for the heir/heiress to age up into a Young Adult is a pain in the ass, but I want to avoid cheating. These are super serious issues, ok?

I have a family with three generations. But they're static, so I started out with generation two and three and went back on generation 1 afterwards. I linked them all together with cheat codes. I don't think I would like aging my sims..

I've only made it to gen 3, with gen 4 ready to be harvested.
My first save was deleted in a fit of rage after a particularly bad crash, others I did not want to have babies or, since I play in rotation usually, never got around to it, or I lost interest.
My current save has lasted so long because how pretty the family is, lol.