Wow, the yarns some mechanics spin when that next boat payment is due
are truly amazing!  Find another mechanic, you will go broke if you
continue to visit this fellow.

It sounds like he is referring to the thrust bearing at the center main
bearing in the engine, and I wouldn't be worried about this wearing
out.  I've never seen one wear out, but I'm sure through some sort of
abuse it is possible.

Clutches should last from 80,000 to 100,000 miles or more, depending on
how much you use it.  Hills, stop and go driving will put you in the
lower end of the range, and mostly freeway driving will get you farther
between replacements.

The clutch kit itself is $100-$120 from the list vendors, and it should
be a two to three hour job.  Many shops flat rate clutch jobs in the
$500-$600 range however, they are a good money maker for them as you can
see.

Drive until yours starts slipping and then replace it.
--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Daughter's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT