I decided to replace all of my containers with these gorgeous (although pricey) containers. I mainly use them to store cold items in the refrigerator, but we do occasionally use them in the microwave. However, recently I noticed cracks in several of them! I take extremely good care of them. They are hand washed (never been in the dishwasher) and they have never been in the freezer. I bought them mainly for their appearance and the seal. Will not purchase again.