Walk out to the outdoor unit on a clear day and look at it the way an inspector would. Check whether the cabinet sits level, whether the pad is solid, and whether anything has settled or grown against the sides. Leaves, grass clippings, and debris belong in the bin, not in the coil. Keep the space around the unit open as the installation guide describes, and keep stored items away from it.
The filter is the routine you can count on
Check the air filter every month during the heavy heating and cooling seasons. Replace it when it looks loaded, and write the change down. A clogged filter forces more air through the same coil, and that extra work shows up across the rest of the system over time. Use the size printed on the filter frame, and keep a spare on hand so the change is not put off.
Watch the defrost cycle
In cold weather the outdoor coil can frost. The unit then reverses briefly to clear the frost, and you may notice vapor rising from the top or a short change in sound. That is normal operation. What is not normal is ice that stays on the coil after the cycle finishes, or a unit that runs for a long stretch without clearing the frost. Note what you saw, when it happened, and how long it lasted, and have a licensed technician look at it.
Keep the drain open
A heat pump makes condensate water while it cools and, in many cases, while it heats. Find the drain line at the indoor unit and confirm that water runs out of it freely. Check the drain pan for standing water or a sour smell. A drain that backs up is a small job when you catch it early and a larger one when you do not.
Write the record down
Keep a single sheet with the install year, the model and serial details from the nameplate, every filter change, and every service visit with its date and what was done. That sheet gives the planning date its meaning. When you compare your system with the typical service life on the heat pump page, you are comparing it with your own record, not with a guess.
What the routine does not do
Owner care keeps the system clean, clear, and easy to read. It does not replace a yearly visit from a licensed technician who can test refrigerant charge, electrical connections, and controls. Use your routine for what you can see, and book the technician for what you cannot.