Not the person you are asking, but our system is 5 years old and has required two hours of intervention work (zero scheduled maintenance).
A USB extension cable died, and it took an hour for the manufacturer to diagnose it over the phone, for me to find the right tamper bit to access it, then remove the cable.
Another time, PG&E was feeding the wrong voltage and frequency into our house. The power stayed on (our transfer switch knife cut off PG&E) but the solar array shut down because this is a weird fault. Again, it took about an hour to diagnose over the phone and fix (in this case, I temporarily turned off the PG&E service breaker. It ran diagnostics for about 30 minutes and turned the array back on).
Installation (included in purchase) was probably about 100 man hours though.
