It's somewhat true for me. I may be poor, but I dispute being an engineer.

In fact, sometimes I'm surprised by what I did 7-14 days ago. But yes, I can get back into that code much more quickly than if I hadn't written it myself.

If this isn't true for you, you may not be solving hard problems.

Wouldn't hard problems make it easier to remember? If you spent a couple of months a few hundred lines of code, then you probably know it much better than something you finished in an afternoon.

Personally, I can remember pretty much every line of some algorithms I wrote years ago, but I was doing some cleaning the other day and there was a month old abandoned branch I had no idea why it was written.

Hard problems are more unique but often more complex. I can normally remember the gist of how complex things work but the details fade from memory pretty quickly.