How do turbofans and piston-engines compare in terms of maintenance costs? I want to compare piston engines and turbofans on a maintenance basis. Let's say both engines are capable of 100 kN of thrust. Let's say both engines fly for 10,000 hours.

Over that time, what kind of maintenance can we expect from those engines. In particular:


How many times will the engine need major servicing?
How many man-hours does that servicing require?
About how much does it cost to do that servicing?


Major servicing for a piston engine would be something more than an oil change. For a turbofan it would be an overhaul.

Come to think of it, I don't know exactly what kind of servicing goes on for a piston engine other than an oil change. Is it like an overhaul where you dissasemble it and make sure everything fits together properly?

In case you're wondering, I'm envisioning these engines in a commercial cargo role. So no excessive dirtiness or hard throttling.
Your question has some areas that depend on circumstances, models, etc. but to answer in general:


Piston engines are generally fully overhauled every 1200 to 2000 hours or so. Time to overhaul one varies with the engine model, and where the overhaul is done, as it can be done at the factory, at a repair shop, or by a qualified A&amp;P/IA (a field overhaul). A piston engine overhaul can cost as much as $25,000 or more. 
Turbofan engines will likely not require major service during those 10,000 hours. Most turbofan engines are inspected regularly and continue to operate on condition unless manufacturer recommended time periods are reached or exceeded. Time to overhaul varies greatly by engine model. Costs vary greatly as well, but in the case of turbofans you're talking in the hundreds of thousands of dollars.