I removed our door a few years back due to sliding somewhat roughly and a lot of grinding noise. Due to lack of easy locating new roller I just swapped them from side to side. This worked for awhile. After a couple years the rough & grind returned. A couple months ago I gave it a serious look and discovered the aluminum track had mushroomed from years of the steel rollers rolling back & forth. Without even removing the door I was able to hand sand both sides of the profile till the mushroomed burr fell off each side, then knocked off the sharp edges. Now rolls like new! Figure I’m good for another 10 years!