A few questions

You should check for updates each time a new patch is released. All mods/CCs will be automatically disabled by the game, which is a good reminder. It can be useful to note where you got each mods/CCs if you have a lot of them. Also, luthienrising is making a super useful thread each time a big patch hits and tracks which mods/CCs are updated or broken (that's the one for Seasons for example : http://forums.thesims.com/en_US/discussion/941998/broken-updated-mods-seasons-june-2018-patch/latest)

Even if a mod/CC was fine before a patch, it can still break with a patch. That's because mods/CCs are made by imitating how the game files looks like, so if the game files format change, the mods/CCs are no longer using the right format and the game may not understand them fully. It's a bit like if your mods/CCs are talking in old english, while the game is now speaking in modern english.

I usually make a back up of my save file with each new patch too. I haven't used them so far, but since I've been playing with the same save since launch, I'd rather be safe than sorry. :)