Made in China wall clocks are so cheap, less than $10 each, that I have one in every room including the bathroom. The clock movement is exactly the same one found in Dollar Store $! alarm clocks. They all keep amazingly good time.
The bathroom clock is acting queer. It loses an hour a day , fades to losing 2 1/2 hours for the week then stays at that state of time lag. Okay, I changed the batteries not once but three times. Not fixed. I took out the cover and reseated the clock arms on the assumption that they may be rubbing against each other. Not fixed. So I exchanged that bathroom clock with one of the room clocks that had been keeping good time for years. Now the replacement loses one hour a day. The former bathroom clock that I had laid on its side, no point hanging up a flakey clock, now keeps good time. Interesting. Rehung it and its good. Replaced the bathroom clock with one from another room. Same slow down pattern. The former (2nd) slow poke keeps good time once out of its bathroom place.
Any idea what is happening? The closest thing to a logical possibility may be the house electrical wire for the switches running inside the wall. But I don't think that's the cause.