I am just curious how long does a Vision Spinner 1300 normally last? Between my husband and I we have 5 of them, and I am trying to get us set up to last over the summer since my job is just for the school year with summers off and no pay. I want to be prepared so I dont need to order anything over the summer at all. I already have my juice taken care of, now want to know if my batteries 'should' last that long or if I need to get a few. I need to be set through September.