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.