You cannot step into the same river twice.--Heraclitus

And it applies to code. When you look at the code a few months later, you are viewing it in terms of your knowledge at that point. You have learned in the meantime.

We all, for some reason, have a bad habit of wanting a "static" world which we can hang onto like a rock. But "Everything flows, nothing stands still"; so jump in, let go, and "go with the flow".