a lot depends on the company. i have known a few folks that sent back panels that had failed. only ones i know of were lower grade and or flex panels. youtube has several videos where they had some fail and worked with a manufacturer.
i personally have never had a panel fail on my rig or that i installed for someone else.
i am still using the first solar panel i ever bought back in 1997, and it was an old used panel that someone traded in when they upgraded after several years of use.