2005 Pontiac Vibe: when does the timing belt need to be replaced/checkied

There is no timing belt on this vehicle. Vehicle was produced with a timing chain which generally does not need service through the normal lifespan of the vehicle.

No belt. Lucky you. It's a good idea to have someone check the timing chain at 100k and every 20k thereafter. If your mileage is niceley below 100k, that gives you lots of time to find an honest mechanic.