Basically, a ski boot should fit as comfortably as possible and as tightly as necessary. The crux is the frictional connection between foot and liner as well as liner and shell. If there is play somewhere, the whole system no longer works. This means that you can ski better with a really well-fitting ski boot.
During the fitting, close the buckles from the bottom up with only little force. This brings you a little closer to the right fit. For occasional skiers, closing the buckles often creates an unfamiliar feeling: „That feels tight!” Then patience is required. One closes the buckles conscientiously from the bottom upwards to the shaft. The buckles should be tight, but not so tight that they exert excessive pressure on the foot. At the top of the cuff they may sit relatively tight, but should not restrict blood circulation. Then it turns out whether one gets used to the comparatively narrower feeling of the ski boot or whether one really has some pressure points. The flexion of the ankle joint, which is common in correct alpine skiing, pushes the heel backwards. In this position, there should no longer be any toe contact at the front.
If you now have a secure grip and no „play“ when moving, the boot sits correctly. Only when certain areas, such as the ankle or toe joint, still show pressure points or friction a ski boot adjustment has to be considered.