Heart Rate monitor problems

dubbs2009

Hi guys, I have a standard Garmin Heart Rate monitor (came with my 305 a fair few years ago!), I have noticed over the last year or so that it is eating batteries at the rate of about every 2 months... with probably 4 hours riding per week. Is this right? I think the unit might be failing slowly... No chance of warranty replacement due to age - worth replacing? If so which one? Another Garmin standard, or perhaps the premium? Or another? Needs to be ANT+ - any thoughts?

dw300

Everyone says the Garmin premium is rather the opposite. The standard one has served me well for a couple of years so far.