My drivetrain started squeaking slightly after the end of life of my 3rd chain replacement. I decided to not only replace my chain, but also replace my cogs as I usually do on the introduction of the 4th chain. While troubleshooting where my squeak was actually coming from, I thought it seemed like it was the rear derailleur. After lubrication the pulleys were fine but after a couple of days the squeak would come back, so I decided to replace the Pulley Set as well. My drivetrain is silky smooth and quiet now.
After watching a video (probably GCN), I decided to change my Ultegra pulley set (over 5k miles) - they were not trashed at all but rather than wait, just did it. Went with Dura-Ace, NO issues installing - watched a couple of YT videos to make sure ie; install right one in the right place going in he right direction.
For a split second, I thought about much fancier pulley set(s) ie; ceramic and/or oversize.......however, I could not justify the significant extra expense for my level of riding. I'm a Shimano fan boy anyway. Solid bang for the buck & always works
If you are reading this you may have considered. those expensive ceramic pulleys that claim to give you extra divine power. These are very high quality pulleys, with amazing sealed bearings. You won't find them anywhere online except here. They helped to reduce chain noise and REALLY improve shifting in a 105 group.
Bought these because no one had the Ultegra pulleys in stock, mine were shot, and I had a ride the following day. They work well enough but not any better than the originals and wouldn't recommend the switch unless they're the only ones you can get your hands on in a pinch