I normally take a photo of the parking section number when I think there is a chance for me to forget. A long time ago, when we went to Disney World, we were told that if you cannot remember where you park your car, you may never find it! :) That's stuck somewhere in my mind, so I am very cautious of where I park and noting down some landmarks.
Oh my goodness, all the time. The other day I took my husbands car rather than my own and forgot about this fact, and then couldn't find it for what felt like an hour (it was likely only 25 minutes). I've started to take a photo of where I've parked it when I'm in a big car park that I don't know very well.
Once. Never again. Parked in multi-story car park, where I'd never been before. Parked car opposit lift. Went shopping. Came back to level I THOUGHT car was on. Lift doors opened. No car! Don't panic, go down one level. Doors opened for me to see my car! What a relief!
From then on, that would be 25 years' ago, if in strange car park, still park opposite lift, write down lift number, level alpha-character, column number, & where I get out of lift in shops, so I just totally reverse my 'journey' back to my car.
These days I only go to one S/C & in that, have only ever parked in three different sections. There're areas I've NEVER parked, & it's been open since 1979!