Just to add one more voice here, my experience is similar to the OP, I gave up diagnosing and just accept that HR straps need replacing every 18-24 months in my case.
Used to use Garmins, then switched to Polar. I replace the straps first, but the pods become flakey as well shortly after. I tried resetting, fresh batteries etc., the problems always come and stay after 18 months. Maybe it has something to do with how we sweat? To be fair also, I use the HR strap almost daily…
1 Like