I have an older bathtub with a shower installed above with a hose. I will use the tub. After I am done, the faucet will drip and continue to drip until the next time it is used. The next time it is used, it may continue to drip at the same rate, a slower rater, a faster rate, or it may stop dripping. If it stops dripping, then it will not drip until the next time it is used at which point it may start dripping or not drip. It does not appear to make a difference if the shower has been used.
Last year when this started, I had a plumber in who--at great expense--replaced the cartridge. This stopped the drip for about 10 months but now it has started again. The prior cartridge did not have any problems for at least 10 years so a cartridge lasting less than a year seems unusual. (This probably has nothing to do with the issue at hand but, when he replaced the cartridge the only way he could replace it resulted the water temperature being reversed when you turn it on--starts hot then you keep turning it to get cold.)
Any ideas why this is happening?