I'm afraid I have to disagree with Mike on this. (Assuming of course that what I call self-lifelining is the same thing as Mike has in mind - i.e. the climber with a single jammer on a stationary rope hanging by the ladder)
Personally, I'm not keen on self-lifelining on ladders for inexperienced persons, particularly on free-hanging pitches. In my experience the usual problem with novices on caving ladders is that the climber does not get their feet vertically under them, puts too much weight on their arms, loses their rhythm and ends up struggling up the ladder a rung at a time, with both hands on the same rung.
if the person is being lifelined, the lifeliner is (or should be) in a position to provide active assistance to the climber. This is even more helpful if the lifeline is attached to the climber in the small of the back, so as to pull them into the ladder. If necessary, additional pull can be improvised at the top of the pitch with a jammer and pulley or crab to give a mechanical advantage when hauling. (I had to do this earlier this year to bring a tired 16st man up a 30' pitch in the Dales - people who know me will be aware I'm a 10st weakling.)
If the climber is self lifelining and they get into difficulties, they are in the same situation as if they had encountered a problem with SRT (with the possibly complicating factor that they may be in an improvised harness or have the jammer attached to a load-bearing waist belt). This means that someone needs to get down to them and then attach a hauling line to them so they can be hauled up the pitch from the top, or else attach to them directly and prussik up with them in tow. Either option will take time to set up, exposes the rescuer to some danger and can transform minor difficulty on a ladder into a major problem.
Dave