The guide itself shouldn't wear out as there's very little contact there.
I'd imagine if the grease has dried up on the sleeve you'd hear some metal on metal scraping sounds.
When the TO bearing is failing you could have 1 or all 4 of these symptoms...
1. it's screeching
2. it smells like something is burning when you have the pedal down
3. pedal down the car still wants to creep
4. it's hard to shift into 1st and reverse
If you only have 3 and 4, you may only need to have the clutch hydraulic system flushed and bled properly.
It may have air or moisture in the system. Still it's good to check that first.
My clutch TO bearing failed while sitting at a light. The car suddenly wanted to "get going" even though I had the pedal to the floor.
I was only a few block away from home, but when I got there. I could smell burning clutch and paint (of the pressure plate).
In my case, my throwout bearing collapsed. Only repair is to install a new clutch kit (disc and pressure plate)
More here: http://www.fiero.nl/forum/Forum2/HTML/129057.html
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[This message has been edited by fierosound (edited 01-25-2015).]