Battery replacement is difficult, not impossible, but bordering on impossible is restoring the waterproof seal. Once you've replaced the battery you basically have to keep it away from water. I wasn't careful with mine and lost two to water damage after replacing the battery, despite re-sealing with permanent adhesive.
Good to know! IIRC the Round didn't have as high a water resistance rating to begin with, and I typically wear a leather band, so this might not be a deal-breaker for me.
The PTRs weren't diving watches for sure, but the original waterproofing was easily good enough to withstand submersion, as long as the battery hadn't started swelling yet.
