actually i think i meant the cam seals intead of the valves. Good think you ask. Anyways the timing belt takes a lot of work to get to, so these are parts that are readily available when all the taking apart taken apart. So you might as well change it. It takes about a whole day for you to change the timing belt, in most cases you would have to leave your car at the shop in the morning and pick it up later on that day. So why do change the timing belt one day and a few months later your water pumps goes, and you have to retake it to the shop again. Might as well change the part now so be rest assure for the next 100k. I hope that made sense. ANd i also suggest doing the valve timing, and heck why not do a full tune up,(but u can do a tune up yourself). spark plugs, oil, transmission fluid, gas filter. I know this sounds like a lot.but the full tune up you can do slowly, and on your own, transmission fluid one weekend, gas filter next weekend, etc. sorry i went off on a tangent