By year 5 a panel is already down to 95% efficiency. Year 25 is around 80-85%. That may not sound like much but in many environments, that difference is enough to make solar panels not worth keeping. And ask yourself as a consumer if you really think other consumers are going to keep a solar panel because it's "the right thing to do" when they could probably buy and much better solar panel for very cheap at that point in the future. It's like keeping a 15 year old graphics card when you could buy a 5 year old graphics card for $50 and get 100x the performance