How many hours of service do your MTH engines?

I'm sure some of mine have exceeded 100 hours, but I don't regularly check.

I service mine based on miles on the odometer- not hours.

Edit:

You could have an engine from a collection that sat on powered sidings and never ran, or you could have an engine that was run on club nights on a huge track running high speed passenger service at say 75 scale MPH for 5 hours a night.

So one engine in 4 nights racked up 375 miles per night, total of 1500 miles that week, and the other zero. Both have 20 hours, which one might need service?

Ones that I run regularly are serviced every 800 to 1000 or so scale miles which comes out to about 20 to 35 hours. Even this service interval is a bit more often than required. With today's lubricants, 100 hours is probably achievable.

As for the gearboxes, if you have a good grease in it they should go for a very long time.  The factory grease is decent but I always check to make sure they have enough in there, caught a new engine once where they forgot! I replace grease with Red'N'Tacky at some point in the life of the engine and will probably never need to do it again. These aren't high torque, temp, or stress situations, that grease is way overrated for this application.

Hmmm, never checked. They all hit the bench from time to time and get a service look over. I don't check the board's facts.

I should look for fun at the least.

I have a couple that have almost 200 hours on Chrono and close to 3k scale miles.

I service when I feel like it, no set interval. This seems to work- the RailKing Canadian Pacific Holiday Train Engine we run at the Train Garden now has over 12,000 scale miles using this methodology, and that has been on loops with elevation changes/grades the whole time.

The maintenance prompt comes up at 1,000 scale miles I believe.