Yes, we would recommend that the timing belt and tensioner be replaced at the same time, as well as the water pump, if it is driven by the belt. The reason is that labor is the biggest single cost.
Gates, who makes these belts, sells the three items as a kit. Just Google www.Gates.com and you will be able to price the set for your car.
A one time charge of $750-800 or so would replace all those items, making you all set for the next 70,000 miles of trouble-free driving.
My wife has two friends with this Mazda model and they are long lived and bullet-proof.
Happy motoring!