That depends on what situation you are in.
- You are obliged to take 20h of driving lessons if you wish to obtain a provisional driving license with which you can only practice (M18)
- You are obliged to take 6 hours of driving lessons in the following cases:
- Your provisional driving license is no longer valid and you wish:
- switch to an M12
- to participate in the practical exam via the driving school
- You have not passed the practical exam twice in a row and you wish to take the practical exam again.
If you are not one in the above cases (for instance if you have a foreign license), you are free to choose the number of lessons you want, whether or not in consultation with your coach.