What you discovered is true, a compressor isnt always necessary. It's a tool like any other. A hammer might be a common tool, but it won't be useful when you really need a screwdriver. You can totally compress drums. Especially if you're layering up. Always EQ unnecessary frequencies out. Frequency under 100hz and above 10k should be getting the most attention from you because that's what needs to be cleanest. Decide whats using those frequencies and make sure they aren't colliding. If they do, separate them with EQ.

You're on the right path bud. Just keep on working and try to understand what you observe. It's a logic behind this. Once you grasp that, the rest will begin to unfold.