Putting a garage sale dot sticker on an item I am low on after I purchase a replacement. So if I buy a mustard, for example, I put a dot on the one in the fridge to remind me I have one in the pantry.
My iced tea maker
The Libib app for keeping track of what books and movies we own to avoid duplication
My printable packing list. Saves me a bunch of thinking time each trip, and it is organized by section, so if we are going to the cabin but not fishing, I can easily cross off that section, etc.