Years ago I didn't cut mine up, I put the ones I wanted to resist in a safe deposit box, so I had to think before I could swipe.
Recently a friend (with stellar credit even) has told me he was afraid to transfer a balance for lower interest (he's been getting 0% offers in droves, 18+ months) in that he was afraid he might run up balances on the freed up cards. I told him some tricks to avoid it. One, like above, the safe deposit box route. Another, put them in a ziplock, remove as much air as possible, then put that in an ice cream container half full of water, stick in freezer, freeze, then fill with more water to about 2 inches from the top, freeze again and to use them you have to get them out of the ice, melt and chip etc (a note saying "DO NOT MICROWAVE-SEVERE DAMAGE" might not be a bad idea lol). The urge will be gone probably before you can get to them. Or another, wrap in sturdy plastic, wrap that with half a roll of duct tape, before you can get through the tape, the urge will probably fade.
I didn't have too much of a problem with self restraint back then, nor now. I still carried cards with me, just fewer so I had to plan better (traveling for sales and marketing at the time). I've only recommended the scissors route to someone who was really worried they'd go a bit wild with them (we all have impulses and it's easy to forget sliding a card is peeling cash from a roll of bills and fast).
i have used the freezer trick myself. helps with impulse buys, sucks when you need for emergency car repairs 
Starting Score 12-2011: EX 640 FAKO TU 550 FAKO 6-2011