It depends on the level of difficulty how fast I move on. In a Mozart piano sonata I have been able to learn fairly quickly but I have been learning a Beethoven sonata for just over six months now and it is only recently that I am becoming happy that it is beginning to sound like music. Even this would not have been possible without the help of my teacher.
It is when I start to work on articulation that I now recognise the importance of one handed practice in order to improve observation of dynamics, staccato markings, phrasing and accents. Knowing how to read the music from the score rather than just the notes is my main challenge.
I do find that listening to other pieces (usually orchestral) by the same composer does help because the style becomes recognisable without imparting any preconditioning of piece I am learning.