30 things worth tracking with a days-since counter

A days-since counter is for the things you do now and then, where the question is never “when is it due?” but “when did I last do it?”. Here are ideas, grouped by area. Where an official body recommends an interval, it is noted and linked to the guide with its source. For the rest, your own rhythm is the right one.

Home

• Change the sheets. Weekly for most people, per the Sleep Foundation.
• Wash bath towels. At least weekly, per Cleveland Clinic. See how often to wash towels.
• Replace the kitchen sponge. Regularly, rather than cleaning it.
• Check the furnace or AC filter. Monthly, and change it at least every 3 months, per ENERGY STAR.
• Test the smoke alarms. Monthly, per the US Fire Administration.
• Clear out the fridge. Weekly for perishables, per USDA.
• Defrost the freezer.
• Water the plants, and repot them.
• Change the cat litter.
• Descale the kettle or coffee machine.

Health and body

• Replace your toothbrush. Every 3–4 months, per the ADA.
• Replace your contact lens case. At least every 3 months, per the CDC.
• Dental check-up. Every 3 to 24 months, set by your dentist (NICE).
• Eye exam. Depends on age and risk, per the American Academy of Ophthalmology.
• Open a new mascara. Replace about 3 months after purchase, per the FDA.
• Haircut.
• Blood donation.

The intervals above are collected, with sources, in How often should you replace it? and Things that expire that you forget about.

Car and bike

• Oil change, by your car maker’s schedule.
• Tyre pressure check.
• Tyre age. Some makers recommend replacing tyres at 6–10 years, per NHTSA.
• Bike chain lubrication.
• Child car seat. Note the manufacture date; most expire 6 to 10 years after it.

Tech and paperwork

• Back up your phone and computer.
• Review your subscriptions.
• Change important passwords after a breach.
• Service your watch.

People

• Call your parents.
• Message an old friend.
• Date night.
• Visit your grandparents.

How Oncelet helps

Each of these becomes a plate on your board. Tap once when you do it, and the counter starts over. After four entries Oncelet knows your usual interval, so you can compare today with your normal rhythm, and you can set reminders for the ones that matter. The app also comes with 48 suggestions to start from.