LOL wonder what question he is asking
I've used Polar for decades...one of the first 'wired' heart rate monitors in the late '80's or early '90's...it worked then and it does now. I use a H10 and also have a H9, they work flawlessly. I change the battery annually.
I've tried Garmin and Wahoo and they work but sometimes not so well.
My Garmin Edge sends me a warning when the battery in my H9/10 battery runs low.