I have a one handle Delta bath faucet. I estimate it to be about 15 years old. It is just starting to leak ever so slightly (a slight drip. that sometimes stops) Is this a hard repair, is there a kit or is it a rebuild?? Or is it just tightening something?? I am not a plumber and if this is complicated would probably get one to do it. If it is simple I would attempt so long as it is not real deep, and the chance of losing my only shower is small..
They make repair kits that replace the wear items. They are pretty inexpensive (as are the guts, really) If it isn't corroded, it's fairly easy to do. Basically, you pry the plastic cap centerpiece off, unscrew the center screw hidden behind it, pull the handle off, then unscrew the knurlled nut. This releases the guts. You replace the springs and o-rings, and put it back together in reverse order. THere may be some silicon grease, if I remember. It's been years since I did one. Make sure you turn off the water supply first!
You may be able to peruse the instructions at the store and decide if you want. I haven't looked, but you may find the instructions on-line, too. I'd look there. You probably can figure out the kit you need by looking on their site as well.
If you can get to the point where you can loosen the knurled nut, then you can get it apart and repair it. If it is really troublesome, you could spray some WD-40 on it and wait until morning, try again. If not, then you may want to replace it! A plumber may have some other tricks in breaking the nut loose if it is corroded.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013