That's fair. I'll often forget the details or maybe the abstraction isn't good enough, or abstracts the wrong thing. I often have to switch layers, pick up some critical info, and keep that in context when working above. Sometimes it happens often -- forgetting piece A to work on piece B, then forgetting piece B to remember piece A, then having to remember all the intricacies.

I stopped trying. I just write unit tests for the layers and details. It also helps me to keep things simple -- if the unit test is too complicated at a lower layer, then the upper layers are going to be even more complicated. So simplifying that layer is certainly necessary.