I have two kids that still use spill proof sippy cups, and I have to be very careful about how I store them. If I don’t store them right they will crack, and they are about six dollars a cup, so I don’t like to waste them. When I only had my son I didn’t realize just how careful I had to be when I put up his cups. I had about three cups crack on me before I contacted the company that made them to find out what I was doing wrong. They said that I couldn’t put the spill proof price of the cup while it was sitting on the shelf but I also had to make sure that I kept it in a cool place. I realized that I had not been doing either of those things. The room where I store my kids cups doesn’t even have any air vents, and even if it did out HVAC unit is broken. If the AC was working then the back room where their cups are kept stays at least a little cooler then it is when the HVAC unit doesn’t work at all. The room was an add on and since I wasn’t planning on keeping anything but food back there I didn’t have them put in any air vents. I wasn’t expecting my HVAC unit to die so soon after I had the work done so I haven’t had the money to get the unit replaced like I need to. Me and my kids are fine, I go window units for all the rooms, but I have to be really careful about their cups because I can’t afford to replace all of their cups. I am saving all my extra money to get both of my units replaced and I can not wait to have them replaced, then I can stop worrying so much about their cups.