It's been 20 years since I use these brushes. I have one in my main home, another at my secondary home and travel in my briefcase. Positives: - All models use the same charger base unlike electric razors same brand - Use some toothpaste Negative points - The battery can be changed by removing sensitive and provided to the weld. The brush is actually planned obsolescence because the only battery is the same price level as the complete device, which is not the case of a razor or a smartphone. - The OralB brushes are expensive, but there is no difficulty generic equivalent quality brushes third of the price OralB. It should be noted that there are many OralB models whose differences are in the functionality (number of vibrations, timer ...). Finally, I recommend that users do not press too hard on the brush during use: it is useless, especially as brushing should be done mainly on the gum.