We built a house 13 years ago. Raised two daughters using this bathroom. Youngest is now 19.
I guess you have to expect to do some service maintenance on such things. Once in 13 years (with teenage long haired daughters ) is not too bad. I had just removed hair (lots) from trap 6 months before.
Drain stopper jammed. Would not hold water or move at all. Taking cover plate off overflow pipe did not help. Mechanism rod was jammed solid.
Took trap off in basement (awkward with joist, furnace ducts & pipes). PVC pieces easy enough but metal TEE for overflow & horizontal drain pipe off tube up inside hole in house floor and & no easy access.
Finally got a 4" threaded metal piece off metal tee on tub drain pipe and finally could feel with fingers inside horizontal pipe which had no rod running through it as I had expected.
Got on Google and a Lowes.com page
Plunger jammed so tight I had to use a star drill (14" long) reversed so a flat head was against the nearly inaccessible plunger and one solid hit with hammer and it was free.
I finally could remove the plunger & rod assembly up top out of bathtub overflow pipe hole. Cleaned & lubricated with silicone grease. Accumulated crud mostly calcium. Reassembled plunger & trap assemblies & checked for leaks.
All is well.
Even minor job was a 2 hour hassle (mostly with inaccessible trap). A guest bathroom in same house took 10 minutes to fix same way. Plunger came right out up top as it should. This guest bathroom less used though.
Morenuf