Best practice working with Solutions

Hello everyone,

I currently work with CRM 2001 with multiple solutions (ClickDimensions, different vendors, few internal), and I must say it's a nightmare.

Solutions are referencing each other, so when it's time to change the code, or schema (in one or more) and then to import from one env to another, we have so much problems. They often fail to import because of various reason (dependencies, missing fields, etc). Also sometimes asme fields become visible on the form multiple times (I guess because of form merging issue).

So I was wondering what is the best practice working with solutions? Do you separate schema from code, or you pack everything in one? Do you work with managed or unmanaged?

Thank you

Mihailo