I built a pretty complex spreadsheet with several tabs. It has macros and some rather complicated formulas. It works and the client is delighted. That was a few months ago. Now the client wants changes and I am almost clueless about what that idiot (me) did several months ago. Oh, I eventually figured it out and I guess I wasn't really an idiot. Except for lack of notes.

Is there a good, preferred, professional way to document what a mini-application is actually doing so that when it is revisited it doesn't have to be reinvented? I did so in Word by documenting Names, Formulas, Conditional Formatting, Macro, etc. But it seems to me that with the tremendous flexibility we have in designing solutions that there ought to be a sort of standardized way to document our work.

Thanks for your thoughts.