In general, solar panels are built to last. Many users have expressed that they were told that the panels will last for nearly 25-30 years when they bought them. It does not mean that they will stop working after 30 years. They will continue to work. But, energy production will decline after working for around 30 years.  The only thing you will have to ensure is that they do not get any physical damages. There are chances of damage to the panels from external factors like debris and wind.  The reason is that portable solar panels do not have any moving parts. A portable solar panel can break only from within and can be damaged only by outside forces like inclement weather and a poor racking setup. So, if you plan to buy a portable solar panel, it would be good to ensure that it has a rust-proof aluminum body. Also, the legs and frames should be rust-proof. The panels should have heavy-duty latches that can withstand wear and tear. Further, ensure that you shop for a panel that is weather and waterproof.