I've had a few done, If you cant find anything that says its been done or bills get it done its peace of mind.The kit costs about £100ish i think for the belt, pulley and water pump kit i get all mine done at cost + mates rates which is nice, just having my brake pads multironic gearbox oil (£120 for the oil alone!! ) and rear shocks done at the mo.
Make sure to get ya service book stamped up after thou....