this is my second purchase of a generic Dyson V7 replacement battery, the first replacement lasted approx 1 year. The original Dyson battery lasted approx. 5 years, but the item is out of stock through Dyson, it was more expensive at $95, so if this product lasts at least 18 months, I would be breaking even replacing every 18 months with this brand vs the brand Dyson is using.This replacement battery is a different manufacturer from the first battery I bought, so we will see if we get a little longer this time. I will try to remember to repost