When you’re logging long miles and pull into a campsite for the night, the last thing you want to do is take the time to unhitch, just to hitch back up to leave the next morning. If you have a level campsite you can just stay hooked up, but what do you do when the campsite slopes to the front or rear so much that you are unable to level the RV without unhitching?
One option is to raise the tow vehicle, which in turn may raise the front of your trailer enough to obtain level. As an avid boondocker, I encounter this problem quite often. Since you can orient your RV however you want in a boondocking site, if faced with no level options I will choose to leave the nose low.
I then take the leveling blocks I would normally use to level the RV side to side and place them under the rear tires of my tow vehicle. Typically this raises the tongue of the trailer high enough that I can gain the additional lift I need to level the RV with the trailer’s tongue jack, foregoing the need to unhitch.
Another advantage of staying hooked up is that the trailer has little front to rear rocking motion while hitched to the tow vehicle, eliminating the need to chock the wheels or install wheel locks, making your morning departure that much easier.