How long do solar systems last?

Solar panels are normally have a warranty of about 20 years.  They degrade on average 1% per year.  So after the 20 year warranty is up they will still work at 80% efficiency.  Inverters warranties last between 10 - 15 years.  In that time the prices will fall as solar power rises in importance.  Batteries are now starting to see warranties of 10 years.  Good lithium ion batteries that are well managed with last up to 15 years.  Solar systems now perform optimally for far longer than the pay back period, which can be as little at 4 years in sunshine rich Botswana.