Solar systems generally require very little maintenance as they don’t have any moving parts.
A few times a year they should be checked for dirt and debris. A garden hose is often sufficient to clean them though be careful to not spray them with cold water when they’re hot as they may crack. If there is tough-to-remove debris on the panels, a squeegee with a long pole and some soap is an effective way to clean panels and maximize energy generation. Early morning or evening is the best time to wash them.
Solar batteries last about 10-15 years and panels last upwards of 25 years. That being said, inverters often need to be replaced every 5 to 10 years. Most batteries come with a 5-year warranty whereas panels come with a 20- to 25-year warranty.