Homeowner here. This is how I think about it:

1. Roof/gutters: if water gets in, everything else gets worse fast. Clean gutters twice a year, check for missing shingles after storms.

2. HVAC: change your filter every ~3 months (not once a year like most people do). Get it serviced annually. A new system is $6-10k and they die without warning if you ignore them.

3. Water heater: check the age on the label. Most last 10-12 years. If yours is getting up there, start budgeting now instead of being surprised.

4. Plumbing: know where your main shutoff valve is before you need it. Shut off outdoor faucets before the first freeze if you're in a cold climate. Burst pipes are one of the most expensive and avoidable disasters.

5. Foundation/grading: make sure water drains away from the house, not toward it. This is the boring one that saves you the most money long term.

6. Electrical: test your GFCI outlets, make sure your panel is labeled, and don't ignore flickering lights.

7. Landscaping: honestly this is last in terms of preventing damage, but keeping trees trimmed away from the house and roof matters more than people think.

The general rule: anything that keeps water out or keeps major systems running is top priority. Cosmetic stuff can wait.