i would have it done at 70k ish i had mine done then. on alot of focus's the tensioner snapps not the belt its self! so go for the whole kit! alot of them have snapped WELL before 100k or 10 years!

as for spares are you after new or second hand? if new sign up as a paid memeber of the ffoc and tezza should be able to get you discount if second hand ebay or scrappy!

alex