This is my first season riding in the BC, so 1 set of batteries should be me through an entire season without needing a replacement?
If it makes any difference I'm using a BCA Tracker DTS
Depending on how much you go, probably not. I generally replace the batteries in my beacon once the power level dips at or just below 70%. The reason being is that even though the battery drain is even, in really cold temps the power levels can drop considerably. Batteries are not that expensive. I generally do close to 60 days bc riding every season. I replace my batteries at least twice during the season.
If (I believe this is the battery type for the DTS) triple A batteries are hard to come by in Japan, order a set of alkalines now. I generally buy the 24 packs and throw them in my gear bag. It is also not a bad idea to carry a set of four batteries in your pack or as my friend does, taped to his beacon harness strap. Makes for a handy quick swap should your batteries be dead. More importantly, they can be put in your friends beacon who has dead batteries.