OK, let me see if I can understand what you are saying. You should realize that the rules for driving lessons vary per country, like in the Netherlands you can only practice with an instructor, and not with any other adult until you passed your theory and practice test. There is no limit on how many hours you need to have practiced; if you decide to go up for the practice test with only 1 hour of lesson, and pass (VERY unlikely), that would still be allowed.
Based on your messages, I am assuming the following - please correct me if I'm wrong:
- Susan is your driving instructor
- now you have her permission, you are also allowed to practice driving in your parent's car while they teach you
- actual driving lessons with Susan count 3 times as much as lessons from your parents
- you currently have driving lessons with Susan twice a week
- you record all lessons in a logbook, and need to complete a certain number of hours before you can take the test
- you are not getting driving lessons with Susan unless you have worn your belt for 4 half-days in a row
- you don't currently wear the belt at nights at all
- wearing the belt every afternoon now feels to you like it is possible, and perhaps easier to get used to than occasionally.
- you have freely agreed to this new set of agreements, but are still unsure where it will lead to.
- I can find no information on how often your parents agree to practice with you, and if that is included in the 4 half-days continuous.