I have downloaded the Story Progression Mod for The Sims 2, and realized that playing with it makes the game develops much faster (obviously), in a way that the normal lifespan seems really short. This could be solved by downloading mods that increases the lifespan; but the problem is that there are some neighborhoods I wish I could play the normal way, whithout story progression (just to have a little more control over things, plus the fact that Story Progression is a huge endeavour being udertaken, and there are some glitches to solve as well), and, whithout it, we get the opposite problem; sims would take eons to age. Now, we can turn Story Progression on and off for each neighborhood; what I would like to know is if there's a way to 'turn the lifespan mod on/off' for each neighborhood as well.

What I would do is make a different 'The Sims 2' folder. Just do that by renaming the folder in the EA GAMES folder in your documents and load the game up. It should generate a new one. That way, you have a game with your normal lifespan and another game with an extended lifespan (just place your new aging mod in whichever 'The Sims 2' folder you're planning on using it on).

Yes. Making different folders for this is a must. I made the mistake of trying to swap out mods in different saves. It’s very easy to forget, open the wrong hood with the wrong mods in place and screw up the hood — especially with story progression. Here are the game folders I have now.

1. Vanilla
2. Story progression (I use normal lifespan because I play only one household per hood)
3. Medieval cc only
4. Long lifespan

You can. Load up their lots and turn SP off for them.

Thanks for the suggestions. I think I do something similar to what kewpie did: I basically have 2 copies of the "downloads" folder compressed in my computer, one with story progression and lifespan mods, and another one without them; I have to unzip the correct "download" folder every time I'm going to play the game. It works, but its kind of a hasle having to do this ever time, I was looking for a easier way to achieve this.

@Eusebio Ptolomeu, instead of unzipping the correct download folder, do what CrystalFlame360/kewpie suggested and make an entirely different TS2 folder. Don't just swap the Download folder in and out. So for example, when I want to have a separate folder I rename my old folder something different (usually something short like "Reg" for my regular game, but it can be anything) and then start up the game. The game will generate a brand new TS2 folder, into which I copy all the shared things I want in both setups, like CEPs, custom music, userstartup, etc. (You can also just copy your old TS2 folder if that's easier.)

Anyway, once you have two folders, put your Story Progression Download folder in one and then the other Downloads folder in the other TS2 folder. The game will only load the folder currently named "The Sims 2" (you might need the TM in the folder name, depending on your game version). This way you only have to rename the folders when you switch hoods. It does require more hard drive space, but it's much easier than unzipping the folder all the time, imo, and often less confusing. This way you also don't have to worry about starting up the wrong hood, like kewpie mentioned, because each hood is always with its respective folder. You just have to remember that you might need to file away new downloads twice, depending on where you want to use the cc.