Ever wonder when the last time you changed your HVAC filters was? Using a bright colored index card, I write the years, with corresponding months, leaving room for my date I changed the filters for the next three years. I make one for each filter location. I attach it to the wall with two hook and latch dots. I also attach a pen this way, so it's always at the ready!
And now I have two checklists for three years: 2021, 2022, and 2023. You can use a white index card and double sided tape to make it very easy. Keeps your unit running more efficiently!
The experts recommend changing furnace filters every ninety days. I don't think this should be a hard and fast rule as there are times when filters can get dirtier faster, maybe during spring cleaning or some remodeling work. A visual inspection of the filters is probably best.
A tiny piece of tape attached to the thermostat would be a good place to write the date of the last filter change. But I always like to learn new things. Please tell us the advantage of keeping a running index of all the filter changes. I feel a little silly, missing what may be obvious to others.
Nice idea, especially if you share tasks with others in a household. I am by myself, and I schedule those filter changes on my Google calendar (along with a long list of other periodic maintenance tasks). It's amazing how much stuff there is to upkeep!