I use to do it automatically, but then there was a video stating it actually helped lubrication, either way it's not the reason for lifter failure.
Though not sure if the lubrication theory makes sense, because if won't come on either when in tow/haul mode even when cruising easy on a level road in 8th gear. If MDS actually helps lubrication, then why on Earth would the engineers devise a system that reduces the engine's lubrication capabilities when it's needed the most, towing?
Most people like to turn off MDS because they have an aftermarket muffler and it drones during 4-banger operations, either way you go, you should be fine.