Change the air filter on time
A dirty filter makes the system work harder and the air worse. The interval is easy to forget because nothing looks broken until it does.
How often
Many homes do well at 90 days. Pets, construction, or allergies may need 30–60. Put the size (for example 16x25x1) in the message so you are not hunting the old filter in the dark.
A quarterly ping
Set a monthly or every-three-months reminder. If you skip a cycle, snooze from the text. See also how often to change an air filter on the blog.