I've owned MANY double walled glass mugs including a variety of different brands. I love the way my morning coffee looks in them and they really extend the time my coffee stays hot, but... They ALWAYS break...eventually. I purchased these on a whim because they were supposed to be the best but honestly, I figured I was probably throwing my money away because...they get dropped, knocked, tipped over by a cat, thunked by a fork....you get the picture. So, the two glasses I purchased, two YEARS ago...they are still with me...YAY!!! I don't know if the original purchase price motivated more caution or if they are simply sturdier, but I will never purchase another brand. They are worth every penny. They look and feel amazing. The amount of liquid they hold is sufficient to keep the beverage hot until it is emptied. I have thrown them in the microwave to heat up forgotten coffee without issue. I wash them by hand one at a time and store them away from other mugs and dishes on a separate shelf to avoid bumps which may be overkill but seems to be working. They are expensive bought in pairs but this set of 8 was a steal. These are everyone's favorite mug in the household whether for hot tea, cocoa, or coffee. Now we have enough for everyone and a guest too. Life is good.