They’re just like regular timing belt tensioners. You usually change them out when you do your timing belt (or in your case chain), water-pump, tensioner, auxiliary belt as part of your drivetrain maintenance.
But since yours is a chain, there is a high probability you drive something German (Audi, VW, BMW) and it’s going to be a pain to change because they’ll probably require transmission disassembly to get to it. I know a lot of people just replace the tension but after awhile the chain actually weakens, stretches, and can snap, which will cause havoc to your valve-train resulting in internal engine damage (piston colliding with your intake/exhaust valve).
nobody drives a pickup? You’re missing out. I went from a 3 series to an old avalanche and now a '17 Silverado 1500. I’ll never go back to a regular car.