It's usually recommended to install solar panels on a relatively new roof (< 5 years), so that both the roof and solar panel lifecycles align. Since the panels

It's usually recommended to install solar panels on a relatively new roof (< 5 years), so that both the roof and solar panel lifecycles align. Since the panels act as protection of sorts, it also extends the life of the roof, and you can easily have both installations serve you for ~30 years.