I can see getting the accessory drive belts changed before the timing belt.
Mine were looking very bad at 99,000 (many cracks). My timing belt looks
perfect at 8 years and 99,000 miles on the outside.
The question is are you willing to chance destroying your engine by what
might be weak on the inside of the belt? My old belt still had just minor
deflection on it when installed. I would love to seen some damage on my
old belt but I can not see any. Remember, the belt is rubber and is
operating in an oven and gets virtually no cooling. Sub zero temeratures
don't help it either. Be safe rather than sorry, change it.