I have a couple of jars that wore out, meaning the bearings were going bad. You can't replace the bearings on these. I bought this a few weeks ago and it's louder and noisier than previous jars when they were new. I was concerned it was putting too much stress on the base/motor. I called and they listened over the phone and said it would take about 100 blends to get quieter. It's still too noisy and if it ruins the motor I'll be mad. IMO if the newer jars have bearings that are too tight, then they should spin them 100 times at the factory so MY blender doesn't have to wear itself out during this "break in" period.