Roofs typically last between 25-50 years, depending on the materials. If your roof has less than 15 years of life left or is in poor condition, you should replace your roof before or alongside installing solar. 

Installing a new roof along with solar can save labor costs — some solar panels are now made to be integrated with roof construction, and solar panels can extend the life of a roof by reducing sun damage.

To determine the age of your roof, you can:

1. Ask the previous owners: Your real estate agent can usually put you in touch with previous owners if you don't have their contact information. They may have records or be able to recall when the roof was replaced. If they don't remember, ask if they can recall the name of the company that replaced their roof and contact them for a date. ‍
2. Check building permit records: You can request a copy of the permit from your county government's office.‍
3. Get an estimate from a solar installer, home inspector, or roofing company: If you're already reaching out to solar vendors, they will be able to help assess the state of the roof. Otherwise, contact a home inspector or roofing company to get an assessment.