I think part of the reason my skiing has improved the past 2-3 years is because of the efficiency I have developed/employed with my skiing and drill work. Many on this forum complain about dedicating too much of their limited skiing time to drill work when they "could be having fun". I think it has been said before but you can come very close to having it all. It comes down to efficiency and never wasting terrain. Certain drills require that one pretty much stop skiing and just do the drill. OFR and TFR are both examples of this where you have to stop, and work in small spot on the mountain as you execute a number of these. Many newer PMTS skiers will not be attempting either one of these drills. But once you move away from these two, many of the other drills you can do in the midst of your skiing. I work SP releases/drills multiple times a day and I have certain runs on my home mountain that are prefect for them. I do Angry Mothers all over the mountain for half a run (or multiple runs if the need arises) at a time multiple times each day. Same for Phantom Javelins, weighted releases, Flappers and the basic Phantom Move (actually not so basic!). I have several drills that are more tailored to the needs of my skiing, generally things have worked in my lesson with Harald and Diana and I work them in as the day progresses especially when I notice that something that needs to be in my skiing was just missing in my last run.
I just came back from 2 weeks in Montana and I skied to my hearts content (12 days, yes I should have taken at least on more day off), skied some great pow just for fun, also skied a ton of bumps and this was very focused. So in the midst of skiing something really fun and challenging I would work drills the rest of the way down or take a break (legs can only take so many bumps without a break) and ski groomers doing drills that I need when skiing bumps. I also ski with my wife a good amount in Montana and she pretty much just skis groomers and although a decent PMTS skier she is less advanced than I am. That time with her is great to continue to work drills and ski bumps on the side of groomed runs where she is skiing.
Several years ago I would find myself coming back from week-long ski trips where I skied a ton but knew that I had not moved the ball forward with my PMTS technique. I am not sure when I made my mind up to not let this keep happening but once I did I started to notice all the opportunities to work on so many different essentials with so many different drills while having fun freeskiing during a vacation day.
Learn from the best, Harald is working on his skiing every turn. All good skiers are doing this, working on their skiing every day , every turn, all the time. It only sounds anal but its actually quite fun and a sure fire way to advance. And you will never feel like you did drills and never really got to ski!