I have only had them for a couple of months, so I haven't got that far yet. From some research I have done, I should hose them off once a year. The installer told me that I could probably just hose them off from the ground level, but I'll probably hop up on the roof and hose them off. I'll probably do it next spring for the first time.
Be aware to not hose them off when they have been exposed to sunlight for a certain amount of time. Solar panels become extremely hot and cold water will crack the glass panel.
I've had panels for 3 years now. There's no maintenance needed. Performance is monitored via app and the company that installed them for me will contact me if something is wrong with them for the next 25 years.
Nah, there's no way they saw me with how bright the sun was. Plus, the nearby neighbors know I have solar panels. They had to sign off on it for the HOA. If they knocked on my door and asked to come in, I would gladly let them in. But I'm not gonna go knocking on everyone's door in the neighborhood and invite them in. I can't save everyone.
I’ve had solar panels and a battery for almost four years. Other than cleaning the panel surfaces once or twice a year they have been fully maintenance free.