Operate 4WD 10 miles per month?

I've never seen anything in our owners manual where it says to run it in 4 wheel drive x amount of miles. It's just common knowledge that it is a good idea to do so.
I will usually put mine in 4 wheel drive a couple of times a month [on a straight road] and run it at a slow to moderate speed for a couple of miles.

I could be wrong but.....that used to be true on trucks that had auto-locking (or manual locking) hubs. Ours are always locked and all parts of our 4X4 system are turning all the time. The only thing you're doing by putting a Titan into 4WD is actually sending power to the transfer case. But when unpowered, it's still turning. Having said that, I still throw it into 4WD every so often while driving on a nice straight road.

True, the Tundra manual says to drive for at least 10 miles a month. It says this is to assure that the front drive components are lubricated.
I rarely drive less than 400 miles a month in 4WD, so that is not a problem for me.