It is recomeneded at 90k... It is expensive and i would only recomend trying it yourself if you know what your doing...
The lowest estimate i can come up with here is $520.00
Make sure they replace the water pump, and the balance shaft belt...both can fail and cause the timing belt to break later, and cannot be replaced unless you pull everything out just like you would have to for a timing belt replacment...
Get it done soon, just because your engine runs fine is NO sign of a good timing belt, your belt would have to be stripped of teeth, half of it missing or streched beyong belif for your eninge to start showing signs, and by the time it did the belt would break and a 90% chance of you shopping for a new engine...
The belt on my car broke, well not broke it got stripped and might as well have broke when the intake cam locked up becasue of the rotor in the igition wasnt the right one or somthing (it was a cheap one from shucks, always go OEM
) And mine came out fine from this, but that is RARE