usmile Electric Toothbrush, is this battery too durable?

I haven't charged it for over half a year, while my other Philips toothbrush needs a recharge every one or two months. I don't notice any difference in usage, even though it's five times more expensive than usmile. Suddenly, I feel like I got scammed.
And the Philips shaver I bought also doesn't perform well; both the battery and blades are poor quality. Flyco is also 🥲.
Oh, and the Philips eye protection lamp I bought earlier also didn't work out. Truly a warning to avoid.