How do you know when your thermometer/hygrometer needs new batts?

[Aneesa's Muse]

Yeah.. how do you know? Is it when the temps start being goofy in an incubator that holds steady all the time? Is there a time frame that I should be aware of?

I ask because my therm/hygro 'meter is fluctuating from 97F to 102F within hours ..and the ambient air is stable in that room ....and this little incubator has not been unstable for me.

Thanks!

 

[chickenlady]

I put new batteries in for each and every hatch whether it needs it or not. I dont want to take a chance.