Hi! was spending the sunday afternoon reading up some mags, and the thought came up - can I use rechargeable cells, and save a few bucks? i have a nikon f65, and it uses two CR2 cells - my first set lasted me 10 rolls! from this perspective, do you think it's worth going in for rechargeables? how long do they last, ie., before they're ready for the bin? also, how much do they cost? and how much does the recharge-unit cost? thx!