I use mine all the time. The only time I turn it off is as was mentioned, in hilly terrain or in traffic. Good thing for me that doesn't happen all that often between here and the beach!
Seriously, as long as the tranny isn't hunting or shifting frequently such as up and down hills, you're fine. Why not be just that much more comfortable? Especially out here in rural S. Central Texas plains, not a lot of hills or traffic (except for in the shale region) but lots of wide open space and long long drives to get anywhere; yup, I'm glad to have cruise control on those kind of drives...
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!