After about 8 years of ownership, an occasional spray down from my hose for washing off pollen and a look at panel production once a month shows my system still doing as good as year 1.

Yes, for my FL, PA and markets like that it is normally closer to 6-7 years.

Often the solar I'm helping homeowners get installed in CT or Massachusetts is paying for itself in about 4 year. Not too bad IMHO.

There are other comparable or better options: Franklin aPower2 15kWh battery, enphase 10kWh 10p battery are ones that come to mind first.