I installed an American Pro-Line Flame Guard 40 gallon gas water heater in 2013. In 2019 the pilot went out and wouldn't stay lit, so I replaced the thermopile (and pilot lite) assembly and all was well until the pilot went out again about 3 months ago, but this time I was able to easily relight. Then during the next week the same thing happened about 3 more times and then 10 weeks went by without a problem, and now for the last week it's gone back to the every other day schedule. It would be cheap and easy to replace the thermopile again, but I'm having a hard time convincing myself that it could fail intermittently.