What is the reliability of solar panels and inverters?
There are some parts of a solar system that you should never have to worry about and other parts that are more likely to fault. From an experience as an installer writing this FAQ I have replaced less than a handful of faulty solar panels yet somewhere between 300 and 500 inverters since 2010. Solar panels are manufactured with minimal components and the major issues that can arise from solar panels is earth leakage from the panels. This is where moisture gets underneath the glass panel and allows voltage from the panel to get out onto the frame of the panel. This and connection issues this MC4’s (terminals to join the panels together) being not installed correctly are the major issues that you may find with a solar system.
Inverters though have a lot more components that can cause an inverter to fault and stress on the components. If installed correctly there is not a lot you can do to prevent issues but note that installing a better quality inverter will give a lot more confidence in the reliability of the inverter. The other major component is the railing which if installed correctly should not show any signs of issues with in the 10 to 15 year warranty which most have.