It's always good to remember that battery life in sports watches (aren't they smart?) can last a whole week, and some models even have complementary solar charging.
I have a Garmin Instinct 2 Solar. The Solar feature is more of a gimmick, unless youre out in the sun the whole day for weeks it doesnt really make a difference.
But it doesnt matter much, the battery lasts 3 weeks. Its a great watch if you like the old-style digital watch screens