My mother had a rather nifty scooter more or less just like yours, although had a basket on the front. When she passed away, I advised my father to keep it, which he has. Unfortunately he has not bothered looking after the battery and it is kippered, so I would say that if you do not use it often, charge it every 3 weeks or so, as batteries ain't cheap.
Your piccy brings back some good memories as we had great fun with my mother, as she was a bit nervous on it and she didn't half pull some fine stunts...lol...My youngest used to love travelling with her 2 up. I used to love pulling 'wheelies' - great fun - but then again I am small minded - still great fun!!
Regards