The first one went out after a little over a year. As there are no bulbs to replace, I had to replace the entire fixture. Thinking it a quirk, I replaced it with the same type. A few months later the second one went out. Recently the third one started flickering. I picked up more traditional bathroom fixtures at the beginning of last month, but then promptly put out my back.
Since my back is better, and since the sun will be setting an hour earlier tomorrow (see previous posts on Daylight Savings for my frustration with that issue), I decided to make the switch today for the two that are demonstrating problems. The replacement fixtures were significantly more frustrating to install, but the task is done and our bathroom is fully lit again. I'm just not looking forward to dealing with the other two (which includes the first one I replaced) should they start acting up.