Assuming you mean 'kilomiles', then the answer is NOW.  Timing belts should be
done every 30k miles (with a retension 2-3k miles afterwards, and a retension
at 15k miles).  Rollers/etc every 60k miles.

It is highly recommended to use The Tool to tension the belts.  If your mechanic
doesn't have one, then you may want to look for a different mechanic that is more
knowlegable about 944s.

If you measure in kilometers, make the apropriate conversion from the above.

When the timing belt goes, it takes the head along with it.  So postponing
this essential service is false economy.

Walt - 86 944 NA

You might start getting a little nervous twitch at around 40k. I drive
mine aggressively and change it at 30k figuring it's a weekend of my
time and a cheap insurance policy against bent valves, etc.
don
87 944na currently undergoing clutch surgery.

as others said, belt change interval is 30K miles - stick to that.  My
high risk technique was to drive until I felt the balance shaft break,
then change - I got more miles than 30K, maybe closer to 50K, and
never broke the timing belt - but then again I was aware of this
phenomena.  

I changed the rollers once in 250K miles - they are cheap, changing
more often is not a bad idea.

I don't have the magic tool - after 87 (or 86?) you don't need the
tool for the timing belt, but earlier cars are not self tensioning. If
you have a good feel for these things, you can get it right with a
"calibrated thumb" - and some care - too tight and it whines, too
loose and you can see the belt flap.

the work is not hard to do, the factory manual is very clear on what
to do - but one caution - if you have the self tensioning type of belt
(with the spring tensioner) - REMOVE the tensioner to change the belt
- you really can't work the belt around the roller (I tried, it cost
me a valve job) - this is the voice of experience.  Also, newer idler
rollers are plastic, early ones are metal - I have seen the plastic
separate from the center part of the idler, and the results are not
good.

Bill

www.wbnoble.com

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will iam_  b_   No  ble   at  msn  daught   com