About importing data to existing models and prefabs

Hello!

Did not really know what to name the title but I need to ask you something, but with the following premise;

I was working on a character in Unity and had everything set up. So after I got the character with animations set up, I was thinking "Hey, what if I changed this characters clothes, just to try it out?" So back into Blender, got the new model for the clothing and set everything up right there. Everything was working fine and I exported the character without animations, just a regular T-pose, to Unity.

Back in Unity I set up all the materials and thought "I still have the animation data (using Animator in Unity), but surely this cannot work out of the box. But what happens if I apply the animation to the new character version?"

So I applied it and everything was working fine, the new character worked perfectly with the old animation data. So I said to myself "Wow, awesome! This is great, I dont have to go back and re-animate everything with the new cloth that I just added". But I couldnt help but ask myself "Why? Why does this work? What can I reuse more than old animation data? Cloth models too?"

That is why I am here... What new stuff can I add to my character until it breaks? The clothes and all is parented to the rig, and the rig is keeping it's structure. But I had no idea it would actually, practically, work as perfect as it did. What can I change more on my character? Because I would love to be able to switch clothes, animations and more on the fly.

Edit: I am asking this because I want to plan a good workflow to use with Unity.

Thanks.