Searching this topic and it looks like a long time has passed, why no replies?
i take it from lack of response that this is not so much of a d-i-y maint and repair forum as for some of the other car groups, e.g. bmw 5 and 7-series, porsche 911, etc...
It seems funny that there is no discussion of actually just inspecting the timing belt by pulling off the plastic cover and looking for signs of wear or distress. If it looks bad, its time to do it. If not, then save up till it does.
It also seems funny that (according to Haynes) you have to remove the windshield wipers, wiper motor assembly, and vent cowl, etc. in order to do the timing belt. i'd be willing to bet that the mechanics who do this job have some time-saving tricks to get this job done quickly and beat the book time.