Not trying to start an argument, and it's not my job to judge another angler's program, but.....
A worm will catch lots more trout than a fly. Dipping your flies in sardine juice will catch lots more trout....etc. When I'm fishing, I try to cast to rising fish of any sort, or fish a spot that just looks fishy. Hooking a fish in either of these two situations is the sport for me. It's not a numbers game in any way, shape, or form. I know a fly fisherman who fishes for bluegills, and keeps an exact count. Nice guy, and a very good tyer, but I've never understood that. In any case, if you feel like you're not catching enough fish and a bobber would help, go for it. There are other things you can do as well, however. I've found that using a gold bead on a nymph causes fish of all sorts to strike hard enough that detection is quite easy. The gold bead might be tacky to some, but at least it's hidden underwater.
You can often see a fish take a nymph, and clear water with polarized lenses helps a lot. Rip is 100% correct about getting used to nymphing, and many anglers have written about art of detecting a strike (usually as a result of frustration). Does the solution lie in better line control and practice at the "art", or using a bobber? One of the best things you can do is find a spot on a stream that holds a bunch of bluegill, and drift a nymph past them. Even these fish are capable of a subtle strike, and you can build confidence by catching them without a bobber.
Nymphing is something that I've only done regularly in the past 6-7 years. I think it was when I began setting the hook at the slightest hint of a strike, that I became confident enough to use nymphs often, and leave the bobbers on the store shelf. Setting a hook when nothing is there is fine. There's no limit to the number of hook sets, and trusting your instincts will go a long way.