The DE thing looks sort of enticing, but I'm half Asian and only need to shave like every other day...  and it's not like I can grow a beard like I'm some sort of Canadian even if I tried.
So I've been on Mach3 blades for years, and I change them when they begin to pull at my hairs instead of cutting well...  and I think that's like every 3 months.  I hear white dudes talking about getting only 3 uses from a cartridge, and I'm like WTF??
Anyway, I buy packs of blades from Costco or if some deal comes up where I can get 8 or 10 blades for $13, I'll jump at that (it's happened), and I'm set for a couple of years.
Some people claim to get blades (or maybe disposables) for free by playing some sort of coupon and drugstore deal game.  Seems like a lot of effort, and I've never looked into figuring it out.
But back to the DE thing...  it does look enticing, but it also looks like I'd need to be careful and take my time while shaving.  This is a process that I do early in the morning while in the shower and without a mirror.  With as few blades as I use, and the potential to kill myself due to carelessness...  I've decided against DE on multiple occasions.