My 5-in-1 hit the 14 month mark last month. Batteries in the 5-in-1 show that they are okay, but I thought that rather than getting informed of the need to change batteries in the next few months when the cold hits, it might be better to do it now. If you've hit a year on yours it might be time to consider doing it now if you are in a zone that gets cold. We hit 79 today here in STL and that is pretty unusual. Last week we had our first hard freeze at 24 F. So the cold winds will be here soon.