well, i just hit 100K miles last weekend as i drove to the supercross races in (argh!) Minnesota as i got 31 mpg.
anyways, i was planning on changing it at 100K, but i looked at it again, and it still looks good. it slaps around at start-up, but stops after warming. i think ill get some washers and raise up my plastic cover.
but i did talk to a salesguy at a local dealer, his daughter has a '96 zetec with 105K. anyway as she pulled away at around 15mph, she threw her timing belt. it did cause damage he said, but they hadn't looked close enough to see how bad. i dont know if this is true as far as damage cuz ive heard it is a non-interference engine. i will gamble for 150K unless it gets deafly loud or something lacks performance wise.
however, i am changing plugs, wires, rotor or whatever these have.
wait til at least 100K, if not you're wasting money. salesguy told me 200 bucks to change it-total. :p