Zippo problem; Need to be refueled every 2 weeks, is it normal?

if you have to refuel it only every 2 weeks then there's nothing wrong with it also the fluid will evaporate to,ive had the same zippo since 1975 and still use it everyday and i have to fill mine up about once a week but that my choice its not out,but i also let it set over night before i put it in my pants pocket,those lighter fluid burns are tuff