How are you able to use a blade so many times?? I guess it is pretty different from a DE blade?

Yeah, GEM blades tend to last longer than DE blades. I can pretty comfortably use them for 20-25+ shaves.

Does the comfort of the shave degrade over the life of the blade?

I don’t think the comfort degrades too much, but you’ll definitely notice a drop in efficiency over time. Often palm stropping the blade will bring it back into a usable place, but sometimes it’s just done.