Depending on how you use it, it can last up to 30 days per charging cycle (endurance mode; varies by model). On average, you can get around 7-14 days per charging cycle. Full usage mode has the most aggressive consumption and the battery life is short. However, it can be recharged in around 1-2 hours, from 0% to 100%.
Note that the Alfa Watch use a traditional battery, but it lasts around 365 days (12 months), and it can reach up to 18 months.