They do, but they hold up a lot better than you might expect. A high-quality panel will only lose about 7 or 8 percent of its efficiency after a decade. After 25 years, they’ll still be working at 80% capacity. Will your car do that? Rhetorical question. Of course it won’t.
Some more things to think about
Considering the payoff for your system is less than ten years, your solar system will give you many years of pure cost savings. Additionally, most people agree that more advances will be made in the efficiency of electrical systems in your house. For instance, It’s likely that you’ll replace your air conditioner with a much more efficient one long before your panels wear out, so your investment should remain viable for a long, long time.
Lastly, the cost to just replace panels is quite a bit lower than the cost to install a brand new system, since most of the work is in the structure. When your system finally does wear down, it will be a lot cheaper the second time around.