Batteries last exactly one year and then have to be changed. Which is basically normal. My strap, even after 5 years of wear every day, did not rust, but after a year it stretched enough, because. The design of the strap could have been made more rigid. They go exactly, I set them up once a year, immediately after replacing the battery (which is actually natural). As for water: I wash my hands and dishes in them. I only take it off when I take a bath. No sealing issues were found.