I see dozens, if not, hundreds of people struggle to get their first dunk on a certain rim height (whether that be 9', 9'6", 10'), But, I go into detail as to why it's not as effective going after a rim height that you just can't handle yet - both physically and mentally. When you try to dunk on a 10' rim 2-3 times a week for 45+ minutes at a time but your max* dunk height is 9'6" and you can only get it 5-10% of the time, you may be doing more "harm" than good. I compare this to lifting: You wouldn't do working sets of 475lbs, on squats if your max is only 415lbs., correct? Trying to consistently lift an amount of weight that you just physically cannot will cause your form (technique) will change/suffer and your mental and physical confidence to drastically decrease. If your max* dunk height is 9'6", get to a rim that's 8'6"-9'0" and build positive muscle memory and positive reinforcement over time which will healthily and effectively build your vertical over time. Listen to the rest of the video for a more in-depth explanation. Keep grinding!