One of my “aces in the hole” is what is now a 15-year old Delphi application, and I wrote every line of it myself.   (All 350,000 of them...)   Today, when from time to time I go back and look at it, it’s absolutely the work of a stranger.   O_o   I can’t even find the subroutines in it ... except ... for the trail of breadcrumbs that I left everywhere in that source-code and in the developer documentation that I wrote for myself.   Today, when I read those documents, I don’t recognize the author and I feel very much like I am learning for the first time.

Hmmmm ... does this mean I’m getting old?   I forget.   Uhh, what was I just ... oh, hell, where are my car keys?

Seriously, I see this all the time when I’m working with a former-developer of a large system.   (We all do.)   There is a genuine look of puzzlement, and a genuine re-learning process.   Sure, I’m journalist enough to pick a headline scenario that will grab the reader’s attention, but, even in the “non bread-truck” case, software is very difficult to write the first time and even more difficult to re-understand in the future.