How do coil counts affect a cheap mattress?

When you shop for a cheap mattress, inevitably you're going to hear about "coil count", which refers to the number of coils in the mattress. A premium full-size unit will have 400 or more coils, a low end might have 312 coils. Most people can't tell the difference between a high or low coil count and the durability is about the same, so cheap mattresses with lower counts aren't necessarily selling you short. Another mattress buzz word is "coil configurations", which refers to how the coils are organized, that is, into "hourglass", "individual pockets", "sense and respond" coils--don't give it much thought. These configurations also have little effect on the overall performance or durability of the mattress.