:0) Just checking... I've seen way too many people just go to ponds and pick up sliders or find box turtles only to release them later because they got too big or sick or they were moving or something. Not only is that generally against the law, but also really unsafe for natural populations. Also, in some states it is illegal to keep native species as pets (however, I don't think that is the law in Arizona, you can call your regional Department of Natural Resources to find out).
Make sure your reptile store is getting them from a reputable captive breeder and not just going to a pond to pick them up. A store around here used to do that and now it's difficult to find some turtles in certain locations where they used to pick them up from.
I'm sure you knew all that stuff, but just in case :0) I LOVE turtles and I'm trying to do research on native populations of red earred sliders around here and just want to protect all the native turtle populations I can.