Q: I'm told I need my timing belt for my 2011 Hyundai Accent replaced.

Under ordinary service conditions (i.e., as opposed to "severe" which would be lots of city driving and idling, trailer towing, etc.), Hyundai recommends that you replace the timing belt on your vehicle once it reaches 90,000 miles. At that mileage, it is also optimal to replace any rotating elements (idler, water pump, etc.) that run off that belt simply because those parts do not last forever and those parts are often immediately accessible when the mechanic is already "in there" replacing the timing belt. At 90,000 miles, it’s not a bad idea to replace accessible front engine seals, too, as, for example, the crankshaft oil seal is a very common point of oil leakage. As far as the individual engine ignition coils are concerned, they are no different than any other part on a car. If a valid diagnostic test has revealed a fault in a coil(s), they should be replaced. On the other hand, if there is nothing wrong with them (that is for the ones that test good, no faults), they should not be replaced.

Although your question does not imply this circumstance, if you do happen to currently have a leaking water pump and the required replacement of that pump has led to the mechanic’s recommendation for an early replacement of the timing belt, and the other components you mention, because the timing belt drives the pump, in terms of the economics you probably are better off having all the work done "now" at one time, rather than have a water pump put in "now", only to have to re-open everything to install a new timing belt in 18,000 miles. If you do have a leaking water pump, and you want a second opinion, and also likely a lower estimate for all the tasks you have identified, simply request a cooling system leak inspection and note to the scheduler that you might want to coordinate the water pump replacement with other repairs such as replacement of the timing belt, associated parts and engine seals. If your water pump is NOT leaking, or otherwise defective, and the mechanic has not identified anything in particular that is wrong with your present timing belt, then you need not do anything until you reach 90,000 miles. If you have further concerns or questions, please don’t hesitate to follow up.