Throughout my years of teaching, I have noticed 3 common categories of lesson takers.
1) The “Fix Me” group. This group consists of students who are having a current problem with their game that is causing them aggravation and just want it fixed as quickly as possible. They are not in it for long term improvement. That is not important to them. These students will show up usually once or twice a year for lessons.
2) The “Maintenance” group. This group comes out every year. On average they show up quarterly for swing/game checks to make sure they are doing things correctly and not picking up bad habits. They like new information in small doses.
3) The “Game Improvement” group. This is the group that is really serious about taking their game to the next level. These students will come out for a package of lessons which most commonly consists of between 4 and 8 lessons. They usually schedule the lessons on a regular basis either weekly or bi-weekly so they will stick to the program. They are really wanting to make a leap with their game and know that consistency and effort are paramount. Typically they will do multiple lessons packages and will see huge improvement rather quickly.
No instructor can tell you how many lessons you need. They can try to predict how many based on experience, but it is really up to you to decide which category suits your game and your desires. Obviously all teachers would like their students to be in the “Game Improvement” category as we know it will make a huge difference, but it only will if that is what the student really wants.