A generator that only runs during an actual outage is the generator most likely to fail to start during that outage. Regular exercise — running it under load periodically — is what catches problems while you still have time to fix them.
The general rule: monthly for portable, weekly self-test for standby
- Portable generators: start and run under a small load for 15-20 minutes at least once a month, per our generator maintenance checklist
- Standby (whole-house) generators: most models run an automatic self-test weekly without your input — confirm yours is actually completing this self-test without error codes, don't just assume it's working
Why monthly matters more than it seems
Gasoline degrades within 1-3 months without a stabilizer, seals and gaskets dry out during long idle periods, and small mechanical issues (a weak battery, a clogged carburetor) are far easier to catch and fix during a routine monthly run than discovered mid-outage. A generator that starts easily every month is a generator you can actually trust.
What "running it under load" actually means
Starting a generator and letting it idle with nothing plugged in doesn't fully exercise it — plug in an actual load (a shop light, a fan, anything drawing a modest amount of power) for at least part of the test run. This exercises the alternator and confirms the unit can actually deliver power, not just start.
Seasonal timing worth building in
Beyond the monthly baseline, do a more thorough check right before outage-prone seasons start — hurricane season, winter storm season — including fuel stabilizer, oil level, and (for standby units) confirming the transfer switch cycles correctly. See our hurricane preparedness checklist for the pre-season timing.