While I like the quality of Honda Engineering in general, my understanding is that they're 6 cylinders like you have in the Odyssey have a timing belt that is only reliable for 100,000 miles. On top of that it requires a lot of tear down to replace it and of course putting it all back together. So you're looking at about $2,000 worth of Labor to replace that belt. And since it is an interference engine you don't want to get caught with that belt breaking and destroying the engine. When an interference engine has the valves get out of time because the timing belt broke or the teeth on the timing belt were so worn out that it basically skipped several teeth and became significantly out of time, then the pistons slam into the valves breaking them apart and usually some of the pieces of the broken valves managed to find their way to get caught between the cylinder walls and the pistons and score the cylinder walls. And these engines do not have enough metal left on the cylinder wall to hone them out to a larger piston size. So basically the entire block is a right off. Therefore, the timing belt on these engines should be replaced every 100,000 miles , and most people do a lot of other stuff at that time such as spark plugs, valve gap adjustment, water pump, coolant thermostat, serpentine belt and serpentine belt tensioner, and maybe even new hoses and of course coolant. All these other items don't add a lot of Labor to the whole job because you've got it all apart in the first place ( except for the valves adjustments which requires some time).
However, if it were mine there are many other items that I would do at this amount of miles that would add additional labor and parts charge, I would also do coolant temperature sensors (most have two one mounted on the engine and one mounted on the radiator, and be careful not to mix them up because they look identical but they are different) both O2 sensors the reason it's smart to replace the oxygen sensors is because if one goes bad there's a high likelihood that you will damage the catalytic converter and that is expensive to replace), and maybe even the knock sensor ( don't underestimate the importance of a good OEM quality knock sensor , if a knock sensor fails the engine can lean out to the extent that it destroys the engine), clean the throttle body and mass air flow sensor, and mass air pressure sensor, and if the intake air filter for the engine is dirty replace that also, and also always check the cabin air filter because if it gets too dirty you may not have enough air flow to defrost the windshield in the winter, all these parts add up to about another $1,400 to $2,200 or so maybe even more. Spending a lot of time on the internet to do online shopping of genuine Honda parts can save you quite a bit of money on this type of a job. My local Honda dealer has an online setup that basically mimics the pricing of all the other online on the shopping stores. So OP, my question to you would be has the timing belt done, "replaced", recently that you can expect to get quite a few more miles out of it?
By the way Rock Auto Sales genuine NGK spark plugs at the best price you can find.
Doing all these items ads a significant amount of Labor to the job, especially the valves adjustments because while it's not a hard job to do it is time consuming. And adjusting the valve on these every 100,000 is important because if an exhaust valve becomes too tight the exhaust valve may not close completely and the extremely hot gases right after the ignition are way too hot for the exhaust valve to handle and it will melt the exhaust valve and the seat that it sits in. The small metal pieces that are melted off can get blown out the exhaust or may get trapped between the piston and cylinder wall and destroy the engine. So this is something else that should be done with these engines every hundred thousand miles.
This is how I go over an engine with that many miles so that it's good for another hundred thousand miles.
Also, radiators generally are good for about 15 years and then the gasket that they use to seal the plastic to the aluminum starts to leak.