The recurring and cost and annual maintenance of solar panel is approx nothing. As the solar system installed is non-movable system hence the chances of damage or breakage are less. In terms of performance, the basic requirement is cleaning the panels regularly and taking corrective measures.
There are some points which can cost you some penny during maintenance.
Basically, the solar panel maintenance cost of a smaller PV system is 2% of the initial cost and for a large PV system it’s just 1%of the initial cost