Honestly I am sure there is someone out there that is telling you that you need to maintenance your solar pv system for x amount per year. Bla Bla Bla, so I would say to that if you want to waste your money go ahead, but there is no real reason to be concerned with that. Yes dirt and pollen can build up on your panels, but the average rain fall that we get in lower Missouri is enough to keep your panels clean.
Whether we are installing Micro-inverters or DC optimizers, both of which have a per-panel monitoring system that allows us to get alerts if the system is not performing as it should. If a flock of birds came and covered just one panel in bird poo we would get an alert from our manufacture letting us know which panel was having the issues.
Now... Will it hurt if you wanted to get the garden hose out and clean off your panels before waiting on the next rain? No absolutely not, but is it necessary? No. When we project how much your solar system will produce each year, "soiling" is a factor in those calculations.
You know the cool part is that solar panels are a solid state technology unlike wind turbines that have moving parts. Every body know that anything with moving parts requires maintenance. We like the mentality for you to go with is "set it and forget it" and let us take care of the rest. We will be there for any alerts that the monitoring system gives us.
Solar and Generator Division Coordinator