If it's just a shank and ball set up, no WD parts and bars, then it's not likely to ever need anything other than your keen eye on a regular basis.
Without specifics of load and size, generally the simple stuff is pretty well built if name brand parts. Keep a touch of lube on the ball, make sure it isn't loose in the shank, look at your retaining pin and keeper for wear, bending, cracks, keep your eye on welds (if painted, cracks are usually fairly easy to see. If rusted, sometimes rust can look like a crack.) Anything suspect could be inexpensively Magna Fluxed or just replaced. You could have it welded if you know a good, certified welder, but generally I view hitch parts like lifting parts: when in doubt, throw it out. It isn't worth your life to risk it. Overall, very little to go wrong with a shank and ball. Usually, if something is wrong, you'll know it's wrong. And if it's going to fail suddenly, you weren't ever going to detect it beforehand anyhow.
I inspect air and electric overhead hoists regularly as part of my job. 99.9% of the time I never find anything worth worrying about that needs immediate repair. I often ask myself what are the chances I'm going to intercept an impending, catastrophic failure at that moment? Slim and none, but they still need looked at and documented. A hitch is kind of that way, too. Simple and sturdy, and if it's going to fail suddenly, rather than slowly wear out, there isn't much you're going to do to catch it. Keep an eye on things and use your best judgement. That's all we can do.
"It`s not important that you know all the answers, it`s only important to know where to get all the answers" Arone Kleamyck
"...An unarmed man can only flee from evil, and evil is not overcome by fleeing from it." Col. Jeff Cooper
Sunset Creek 298 BH