So I was searching about this topic but couldnt find an answer

How do you mainain a large save file?

Ive this perfectly fine running custom uberhood I made myself which has Test-Of-Time vibe but Im at generation 7/8 and has roughly 1200 playables in 19 subhoods. . Its currently 1.5GB and increase 50-100MB after i going through each subhood. Most I found were about large neigborhood getting bugged but mine is nothing wrong with, but the rapid growth scares me a little to continue playing it.

Characterfiles is not an issue (its basically just a little bigger than a premade uberhood when including townies) but each sim has alot of memories which increase the save file itself.. The point of this neighbor is to have alot of kids as later generation, there will be plague that kills alot of them so i dont want to do 1-2-kids policy strategies which I know is popular in premade hoods. My sims lives in late Roman empire era By the time i get to this plague, i fear my save file will be over 2 GB.

Ive removed screenshots to reduce the game file size but I dont know what else to do.

Any suggestion?

Keep playing, but backup your hood files after each play session!

You can use the batbox to remove so-called trash memories and boring gossip if you don't care about them. This will reduce the size of the files, I believe (have not tested for myself). I did find that this helped in longer-running hoods that were hanging up when loading.

Before archiving (backing up), I run LotCompressor by Mootilda across lot files which removes screenshots from lot files (mostly a redundant function which was I guess used for the Exchange cataloging). After that, I remove any storytelling photos (though that's because I don't use the in-game storytelling (F4)), and I can't remember if I remove the family thumbnails file. I remove any .bak files from the root folder (e.g. N012 folder), probably generated by the LotAdjuster or similar tools using during my neighborhood-building sessions, as I've already made several actual full backups beforehand, thererefore making the .bak files redundant. Before dumping the folder somewhere (in a .7z, or just a simple folder copy), I run the compressorizer tool across the root folder (all chars, lots and hood files). It's been a while since I've played, so I'm not sure about MB gain from this heavy procedure (nor whether the additional .7z compressing on top of all this actually makes a difference after the files have already been compressorizer'd).

For versioned archiving (several backups in a row), I'd take out the pictures (neighborhood and subhood pictures) and keep those in a separate folder because those are probably the same across the many versions you generate, wasting space as they don't change as opposed to the package files.

I haven't considered removing the trash memories (though I think I have a mod which prevents them from being generated in the first place; I truly don't find any use of having a memory of having met a maitre d' on a Twikkii Island vacation). I've been actually looking into creating a custom memory system using memory manager mods, but I wasn't feeling very creative the last time I spent time thinking about it - thanks for the heads up that it adds up on hood size.