To add to that, how you care for them and maintain them is really important. If you throw them in and forget about them, they won't last long.
They need to be cleaned regularly, the dead bodies in particular have to be removed as soon as possible, since this contributes to further deaths. They also need plenty of crawling hiding spaces in the form of paper towel tubes, eggcrates etc... Moisture is a big must. You can use that Cricket gel stuff or fresh fruits and veggies to provide moisture. I prefer carrots over any other veggie or fruit since they won't mold. And the other big thing is a high protein food. An el cheapo dog or cat food will suffice for this.