You don’t have to. The device is already fully charged, you can use it straight out of the box and you don’t have to worry about charging it for 10 years. The battery provides 10 years of regular training (30 minutes a week) and comes with a 5-year guarantee. If the battery gets empty within 5 years, we will send you a new one for free. It costs $50 to replace the battery after 5 years.