Q&A

It depends on high many miles you have on your Coils and how long you went on the plugs. I would replace my plugs every 60 max. This 100k tune-up story is a myth.

The $240 price for each Coil is pretty steep, seeing as you can get factory Coils for $95 each.
Sometimes Coils will go out if they are closer to something that gets really hot. On German Cars, they are done by 90 k or sooner.
The Coil Over Direct ignition System replaces the wires cap and rotor, so though they it last longer than Cap, Rotor, wires etc, , they still fail at some point.
The Timing Belt is made up of a material similar to tires, yes they now use some kevlar, but not enough to make it 'bullet proof' ( pun intended ), they should still be replaced at 105k or in 6 years. I would also do the other pulleys, , seals and water pump, so you don't have to go back in there.

I had a coil to go bad in the spring of 2005 and another about 10 months later. Have had none since then. I had belt replaced at 100,000 miles. Interesting your coil replacement cost much less than mine. ($600)