At how many miles we need to change the timing belt for a 1999 Mazda Protege?

timing belts need to be change at 60 thousand. miles according to the manufactory cause after that the belt will streatch and will slipAt how many miles we need to change the timing belt for a 1999 Mazda Protege?
why what is it doing

if u want to know ur timming is belt open the oil filler cap and run the car if u see back up pressure comming out from there then that's some valves lacking then yeah u will need to change the timming belts , if ur water pump is there too it's better to change it with it too cause they would probably charge u for the water pump and maybe 30-50 dollars extra it's betterso u won't pay 500 dollars just for the water pump when it go bad .... but timming belt are goods for like 75-120000 miles