Timing Belt

I have a 1998 Contour approaching 90,000 miles. Although not experiencing any problems I am wondering about replacing the timing belt.. at what point should this be done? Can anyone offer any opinion on this? Is there a lot of evidence of timing belt failure at any certain mileage point?

thanks. Larry

V6 or I4?

It is a 4 cylinder

right now, i put 140k on a stock timing belt, thats pushing it but if you don't drive your car hard it'll be fine. Also while your down there replace the water pump if you haven't already.