It actually depends on a bunch of different factors. But as a general rule of thumb, it's a good idea to give your metal roof a fresh coat every five to 10 years. Of course, this can vary depending on things like the type of roof sealant you use, the weather conditions in your area, and how much wear and tear your roof gets. If you live in the Southern U.S., you might have to recoat your metal roof more often than homeowners living in other parts of the country. This is because of the strong UV exposure and heavy rains. It's a good idea to give it a little extra TLC to make sure it stays in good shape.