How I've managed my line has changed over the years since I began fly fishing. For the first couple years, I pretty much stripped all fish in. It helped that most of them were pretty average-sized trout or small bluegills, so it's not like they were peeling much line anyway. But I also didn't manage my line very well, especially when wading, so many times I was stepping on my line, or it was getting tangled in various streamside flora.
One day I really mangled my line after a day on a creek, and resolved to start managing my line better. So for awhile, once I learned to slap my reel rims, pretty much every fish went on the reel.
As time went on and my proficiency developed, I decided that small fish didn't deserve the reel treatment. Unless they were small Ferry fish, which instinctively know that the best way to spit the hook is to fling themselves downstream into the main current. It's amazing to me how much line a 12-inch fish can take when aided by a 20,000 cfs current.
Which is basically where I am now. Most fish don't end up on the reel, but if they put up a good enough fight, on the reel they go.
So, most of the time, I let the fish decide if they're 'reel-worthy.'
Of course, there's also the pure fun of hearing that reel drag screaming as a good fish sprints downstream, and at least for me, trying to slow that sucker down with my palm cupped under the rim is just one of the best feelings in fly fishing. Right then I can pretend that I'm a real fly-fisherman, almost like Paul Maclean.
If you've never put a good fish on your reel and heard that drag scream, you're missing out. And yes, it's even better on an old click-and-pawl.
Peace.