When I get a yoyo, I play it. At some point the bearing gets stuff trapped behind the bearing shield. I take the shields off never replace them, and clean the bearing, with whatever I have, I have used break cleaner, carb cleaner, 97% alcohol, acetone, ect. Make sure it is totally dry, then heavily re lube it with some very thin trumpet valve oil, change the string out every hour for a few hours as the lube comes out. and than never touch it again unless it gets some pad sticker residue in it. than I start over at the cleaning it. I have at least one bearing I have not had to touch again since the late 90’s. it has been a teaching yoyo at a lot of class’s and as run totally unresponsive ever since. Most of my heavily used throws need about every other year maintenance.