We're looking into solar for our home. Payback is around a decade (in Michigan), while the components are warrantied between 12 years (invertor) and 24 years (panels). They should last much longer than that: the invertors typically fail like most electronic components (either in the first six months or so, or not for a very long time), while the panels are still above 90% of initial output after 50 years (again, with any catastrophic failures usually occurring early).
The 30% tax credit in the U.S. is scheduled to start winding down next year, so anyone interested in doing it should make sure their installation commences before the end of 2019.
I'm not sure where you got that >90% after 50 years metric from. I was under the impression degradation per year is about 0.8%. Which should make the panels drop below 90% of initial in 13 years itself.
The 30% tax credit in the U.S. is scheduled to start winding down next year, so anyone interested in doing it should make sure their installation commences before the end of 2019.