In Norway, I started rock climbing, so I bought a climbing harness. When I then did some glacier hiking I bought a chest harness too; on a glacier, you tend to wear a combination harness. On a Norwegian one, at least. And when I then moved to the UK and started mine exploring, I did all the rope work still in that combination harness. And that worked fine! I never did a single pitch longer than 50m, and even multi-pitch trips did not tend to end up too deep underground. That you have to take the chest harness off to adjust it, and can’t get it too tight didn’t matter too much. But once you start doing proper Yorkshire caving this won’t do anymore. The Boxhead Pot trip was sufficient to convince me of that.
One also tends to wear something underneath one’s harness. Even underneath one’s caving suit. I used to just wear old thermals; wear few if you go into a warm, steamy cave, and just add a few layers when you go into a cold mine. And if it gets too cold and wet you just wear a wetsuit. But the incessant crawling in Yorkshire did make me wonder if it wouldn’t be better to wear what most cavers wear: a furry suit. Wearing a full fleece suit (nowadays even fashionable, it seems) rules out the possibility of your upper garments creeping up and exposing skin to the clammy caving suit.
The harness! And it won't be of much use until it's combined with a chest strap, as-and descenders, and some more dangly bits, but that's easily added!
The furry suit. If you call it a onesie it suddenly becomes fashionable!
I’ve now bought both. So in a way, after several years, my kit has caught up with my interests. I’m no longer a caver dressed up as a glacier hiker! And my old harness will go into the washing machine; were I to take up climbing or glacier hiking again it can be put to its original use again!