I replaced a jar from 7 years ago which was working great, actually too great. I blended up a Glass magnet that fell off my fridge by accident as I was getting ice, unknown of course, and it ground up so fine it ground glass into the sides of the blender so I needed a new one. I use it almost everyday and could hardly wait to get the new one. Love my Blendtec!!!  Originally purchased for a business but it closed and I got a great blender to use everyday at home.