I asked the same question weeks ago, the manual is very confusing on this. (I am a manual reader too) It says you must do it to protect your truck, you guys say it will destroy it. I love how helpful Toyota has been. I don't see how driving 10 mi in 4wd could help the truck that much. What is a NOOB to 4WD to do.
Best thing to do if you want to use 4wd for 10 miles each month is find a nice off road trail with a loose surface.