I saw a thread similar to this in the fish section and I did not see any here (maybe I did not look hard enough). I know I have made a few mistakes over the years, some of them led to hurt my animals, some of them hurt me. I think the sharing of our mistakes may prevent the same mistake by others.
Example - Several years ago I loved to use old butter tubs with holes cut in the lids that I could use as hideboxes and water bowls. Everything worked great for a number of years until one of my adult female Spotted Pythons turned a tub over on top of the hot section of the cage. With the hole side down, she could not escape and was killed. After that, I still used butter tubs, but now I put the holes in the curved sides to prevent this accident from happening again.
Example - Several years ago I loved to use old butter tubs with holes cut in the lids that I could use as hideboxes and water bowls. Everything worked great for a number of years until one of my adult female Spotted Pythons turned a tub over on top of the hot section of the cage. With the hole side down, she could not escape and was killed. After that, I still used butter tubs, but now I put the holes in the curved sides to prevent this accident from happening again.