I keep my crickets in a big rubbermaid storage tub with holes cut in the sides for ventilation. The holes have aluminum screen duct taped over them.
I ball up two fresh paper towels and get them quite wet and replace the old ones every other day.
I clean the enclosure and put in new food (see my site for recipe) every other day as well.
One side of the tub is stacked with eggcrate, toilet paper and paper towel tubes, and other various scraps of cardboard to create more surface area and places to hide, which I change out every other week.
This way I can keep 500 - 1000 at a time just as easily as 50 - 100.
My greatest fear is to be out of crickets.
Here's my best hint....
When cleaning the "cricket city" do it in the bathtub. That way if any escape they are easily collected.
-Brad