Talking about the overall lifespan of a solar panel it may live up to 25 to 30 years depending on the installation conditions and type of material used for its production.
Monocrystalline solar panel lifespan.
For monocrystalline silicon the most commonly used panel for commercial and residential pv the degradation rate is less than 0 5 for panels made before 2000 and less than 0 4 for panels made after 2000.
For instance if you have installed monocrystalline panels you can continue to use them without any issue for more than 25 years.
That means that a panel manufactured today should produce 92 of its original power after 20 years quite a bit higher than the 80 estimated by the 1 rule.
Monocrystalline solar panel manufacturers will usually offer a 25 year warranty because of the longer lifespan of the product.