I have a sleeper pc, a little introduction to my sleeper pc is that it used to be an old pc with broken a broken mobo and CPU, I changed those to gaming specs but I kept the original casing and casing fan. Recently one of my casing fans (I have 3) failed. It started to make scratching noises which I figured to be aging bearings and earlier this morning I managed to tear the fan down as it had failed to work already, and found out that it uses a sleeve bearing. There was absolutely no visible lubricant and both the bearing and the Rod (the Rod that sticks in to the bearing). They were both visibly scratched. I added a bit of grease and it started working again although with a much louder noise now. My question is how long is the fan going to last before it eventually fails completely.