As a medical professional, do you think yearly checkups are useful or necessary for healthy individuals in their 20s and 30s? It seems like you've done well for yourself without the need of one due so long.
If you're going to do it, I would recommend having a bunch of labs done so you can at least know how you're doing. For example might as well test A1C, Vitamin D, Iron, Thyroid, Testosterone and many other hormones and vitamin levels to get a good picture of your nutrition. If you're low/high in many of these things a simple supplementation can radically improve your life, but not if you don't know about it. A friend of mine recently found his Testosterone levels were really low, and after starting TRT he feels way, way better. It improved depression levels and many other things, with a bonus that now when he goes to the gym it's actually possible to get some results.
Worth pointing out is that you can have (most) of these labs done without a doctor. There are websites you can buy kits, and you can sometimes just go in-person to Labcorp offices and they'll run stuff for you.
Anyway, just something to consider.