I did about 10 lessons, which were originally very good ... until I suggested that I felt it shouldn't be too much longer before I was ready to go for the test. At that point my instructer stopped teaching me and instead was only interested in pointing out what I didn't know. (I knew that I wasn't quite ready at that point, but thought a few more good lessons would finish it off. Unfortunately it appears he took offence.) Then scheduling changes meant I couldn't get any more lessons.
I then spent the next seven years practicing - ie driving with my husband (who had a licence sufficient to be a supervisor) in the car, though he wasn't really doing any teaching. Finally I went for my test, and completely stuffed everything up. I was too nervous and overcompensated and basically behaved like the first day I had gotten behind the wheel. It was rediculous.
Therefore I took one more professional lesson to give myself confidence, then went for the test (one month after the previous test) and had no problems with it.