Hello,
Honda recommends that the timing belt be replaced at 105k miles or every 7 years, which ever comes first. As with any product made with rubber, it can degrade, loose its strength and snap. If the timing belt should break, the engine will likely be damaged resulting in a very very costly repair. That price seems to be on the very high side. I’d personally look for an independent mechanic to install a genuine Aisin Timing Belt Water Pump Kit (TKH-002, $192.79 on RockAuto). This comes with Timing Belt, Timing Belt Tensioner, Tensioner Pulley, Idler Pulley and Water Pump. I’d also purchase 2 gallons of 50/50 coolant specific for your vehicle and drain the radiator when the water pump is pulled for a refresh of the system. I’d also replace the serpentine belt (Bando 6PK2135, $11.74 on RockAuto). No labor should be charged for this since the serpentine belt must be removed to do the timing belt job.