Hi Rodney-
It was pretty easy to tell in my case- the bearing basically blew apart. It had been making noise for a few months now, so I should have replaced it sooner, but didn't. Currently, I have absolutely no clutch at all.
In most cases it is the friction disk in between the pressure plates that wears out. About 2 years ago, I couldn't change gears at higher RPM's without the gears grinding, but at lower RPM's I could. I installed a new friction disk and everything was good. However, the difference for me was I still had pressure coming from the clutch pedal, meaning the throwout bearing was still good, but the friction disc wasn't stopping the driveshaft anymore.
This time, I noticed absolutely no pressure coming from the clutch pedal, except to activate the breaks. You can also look into the clutch release lever and see the bearing came apart, so it was easy to diagnose a bad throwout bearing.
Also, if the friction disk has thick score marks on it, or the holes where it attaches to the disk driver are elongated, it is time for a new friction disk (this comes right from the service manual).
In hindsight, and if I were you, I would go ahead and do everything all at one time, that way you won't have to worry about it later on. You can try and adjusting it, but if the friction disk is worn, you will never get it to work. I hope this helps.