I failed six driving tests before finally passing on my seventh. I'm not as hopeless as that actually sounds:
I done a weeks intensive driving lesson course and failed the first test - and rightly so, I was 100% not ready.
Second test followed a couple months later and I hand on heart feel like I got a monster tester who was having a hard day and was nasty and put me on edge. I feel I done well in that test but I was failed, and could never understand why. After that, my nerves were shot and I failed over and over again, actually having a panic attack during my fourth test.
Seventh test, when I finally passed, the doctor prescribed me some beta blockers and I was able to keep it together.
I like to think I'm a competent, confident driver and that the many, many lessons have been beneficial. In comparison, my sister also done the weeks' intensive course and passed first time - but she was a terrible, frightened driver for years!
I believe driving instructors say that ~40 hours of lessons should prepare you for your first test. But there is no rule, and everyone should do it at their own pace. It shouldn't be about learning enough to scrape through the test, it should be about taking lessons until you are confident that you will be a safe, courteous, competent driver of a multi-tonne weapon.