
Some will work together but cause an error that will crash your game sooner or later through a cumulative error. Some mods will have numerable sub mods available that are meant to be used either/or rather than stacked. To answer your question specifically, a sub mod is a mod someone made of someone else's mod because they wanted something to be different than the original mod after the original modder rejected the idea in the first place. Add one too many or one incompatible with another and you will find not just an error but a fatal error.

There is no way around this and it does accumulate. Each mod you add on top of another only adds more.

Each mod has its own errors not present in the original game.
