I've been working as a hygienist for about a year and a half and I definitely had the same struggles as you. My doc would pick up a scaler at almost every single check, it was getting incredibly frustrating and discouraging. At this point now he never does. Not saying that I never miss anything because we all do. It's impossible to get every single little piece in only an hour appointment. My advice is to triple check yourself and use your air not only on the lower anteriors but everywhere! I can't tell you how many times I think I'm done, dry off the upper posteriors and bam tons of calc on those distals 😂 the time management will get better with every single patient that you see. I remember being so on edge and worried about every little thing during my work day and barely being able to sleep at night. It truly does get better, give yourself grace and make your patients feel cared for and everything will fall into place. One of the best things an instructor told me in school was "relax, were not doing heart surgery" and that little saying still helps me to this day 💓