Have a microwave with a turntable that no longer turns? The likely culprit is this badly designed part. Not only is this a poor way to design a rotary coupling (just a shaft with a flat) but it is molded from a Teflon material - a material that is known to creep and loose it's shape over time. Note the part in the right of the image, how the top of the part is flared out - that's creep. You may also notice marks from pliers, where I had squeezed this back toward its original shape. That only worked for about a week. The replacement is drop-in, and can be printed from a tougher material. I have had a PLA part in the microwave that has lasted over 6 months.