Borosilicate glass can handle thermal shock better, but I ruined a vase once by not pre-heating enough. The stress showed up after cooling in the kiln. Do you find that thicker pieces are more likely to crack, or is it more about the shape? I'm curious if the cooling schedule played a role too.

But like, is the creak actually causing problems? Might just be annoying, not something that needs fixing right away.

My grandpa still puts sugar in spaghetti sauce because his mom did it during the Great Depression. Sometimes the rules in our head are just hand-me-downs from someone else's survival hack.