What's the difference between a disposable and regular razor?

How long does one last versus the other? I've always used a razor with the replaceable cartridges, but I ran out of fresh ones and ended up buying a shave creme that included a disposable razor. How long should it last for? I shave every day: underarms, legs, and pelvis. I know my old way of buying razors got very spendy, and you can buy large bags of the same brand, but disposable, for a bit cheaper. What's the more economical way to go?|||I used disposable razors for a while and then switched to the kind where you just replace the razor. It didn't work as good for me. Plus it cost more. Disposable razors are the way to go economically. You get a nice size amount and when your done you just pop it in the trash and pick a fresh one!!! Plus you won't feel obligated to use the razor until it's completely dull since you didn't spend an arm and a leg lol:)|||i get disposable mens razors. they're usually better than womens razors and it is a bit cheaper. the problem is that they tend to rust faster and the gel strip doesn't always hold up as well. but i still prefer the disposable ones since they shave just as close.