Just to add my ‘tuppence’ worth.
I’m a ‘fridge’ man. I like fridges. They don’t bend. They don’t have funny bits sticking out the front, and presuming that the unit has ‘ramps’, providing that you can ‘feel’ the weight of the trailer as it rides up the ramps, then there isn’t much that can go wrong. 
Which is also the ‘lazy’ way of doing things. 
However, for whatever reason, a number of companies seem to be ‘speccing’ units without ramps. 
Fail to wind the trailer legs down far enough and you are likely to find the trailer ‘crushing’ the mudguards into the tyres. 
Similarly, if the last user has dropped the trailer ‘low’, then without ramps you could impact the fifth wheel into the headboard of the trailer. 
Matters get even more interesting with ‘Tanks’, or rather, Tanks with a donkey engine welded on the front, or trailers of a similar ilk. You don’t want to be lifting the trailer by way of the donkey engine assembly. Otherwise it will cease to be part of the ‘assembly’. The ‘rubbing plate’, which is the part that one is seeking to make contact with, maybe a foot or 15” back from the front of the trailer.
Curtainsiders also have their own characteristics. The rigidity of construction depends solely upon the chassis members, hence they bend. And the amount of ‘bend’ depends upon the weight ahead of the legs. Pull out without ‘ramps’ and there is a distinct possibility that the rear of the unit may ‘bounce’ and damage either the unit, or the trailer or trailer couplings (dependant upon where they are located). 
Similarly to what was alluded to in a previous thread, I had one, a couple of weeks ago, with double stacked pallets at the front. After raising the drive axle a moderate amount, and then disengaging the pin, I dropped the air in the drive axle, which merely allowed the trailer to bend further. There was still a lot of weight on the unit. After re-building up the air (knackered unit which probably needed a new filter in the air dryer), I sent it up to full extension. Wound down the trailer legs HARD. And it was only then that I could drop the unit suspension and draw from underneath. Leaving the trailer with a ‘droopier’ nose than even Concord. 
From ‘splitting’ the coupling’ to ‘moving off’ took something like 15 minutes, or felt like it. 
Ask a simple question? The answer may be anything other than simple.
