When I was the last one leaving the flat for a while, I put a post-it on the door, not only specifying what I needed to pack (I’ve had that down for years), but also for things to check (open window, balcony). I always checked those things, anyway, but checking (and affirming) that I checked gave me peace of mind.

Weed

Read the last part as that thing your aunt gave you which you don't know what it is.

Story of my life, 9 times out of 10.