Wor Lass, who I suspect suffers from an Obsessive Compulsive Disorder, hoovers our whole house from top to bottom everyday; stairs too. I've seen her run a marathon, get home, and hoover; I kid you not!
She can easily 'knack' a hoover in six months; and three times in seven years; she's broken one before the warranty was up on it.
I always keep the receipts for obvious reasons; but you only get warranty on the replacement item for the remainder of the warranty time on the initial purchase.
It'll be the same for batteries.
Just a thought!