Maintenance

Sure does. When I've calced this out, if you are going to replace a plane with a the exact same model you should keep it for roughly 25 years. This is the equilibrium of CapEx and maintenance cost increases in my experience--YMMV across models. Most people in this game seem to dump planes much sooner, but it's really a waste of money and time to do so.

Even if a newer plane is more efficient, it needs to be several magnitudes more efficient as the newer models tend to cost a lot more than the ones they are replacing. Certain planes are so fuel efficient, CapEx efficient, or unique they should be kept for a very long time (i.e. A340-300,747-400, 757s). Other planes should likely be eliminated sooner when technology advances in the game (i.e. A340 NG models, MD-11) as the models offer middling performance to begin with.

The maintenance base cost for each plane type is incurred monthly for that type on top of the monthly cost for each unit owned. Keep costs low by choosing aircraft that come with a family of other differentiated useful models that you intend to use at some point (i.e. A320, A330, 767). If you buy a plane with no real family, plan to operate many of the type to make it worth the MBC (i.e. A300, 757). Do not buy 5 A320s and 5 737 Classics and 5 737 NGs--will be invisible drag on your financial results.

Russian planes may be different as their CapEx costs are so low that it often outweighs the efficiency concerns and the cost of operating a small family of then is nominal.