Find a way to bottle or teach this and you will never need to work a day in your life.
What are those differences? Being consciously aware of what they are would be truly enlightening and raise any player a level or more.
Then i guess im on my way to never working lol. Honestly, one of the best peices of advice regarding coaching I've ever heard came from a former pga tour player turned top putting coach who works with some of the best in the world, Rory being among his students (sry his name escapes me rn). His advice was to go get a lesson or two while playing ur absolute best. that way u get ur top gear on video and can have a reference for what u were doing. Also, a top coach with a trained eye for these things can point things out to u that u may not notice urself. An example of his own was how Rory had a subconscious imdex finger trigger to his putting stroke that he was not even aware of which was only present when he was'on'. well he made him consciously aware of this and he added it to his routine and his overall putting improved.
The same type of thing can be done with pool players. Tho really, the knowledge gap between pool players and golfers is gigantic and most pool guys simply arent aware of what are considered simple and often taken for granted facts about mechanical consistency in the golf world. I help students understand these concepts and by at least knowing which common culprits to look for, they can better identify and address things leading to day to day differences in how they perform their strokes.
As a basic example, consider 'connection' in the stroke. There is no need to ever not feel that connected feeling in ur stroke and yet many players, even high intermediate guys, have days when they just dont feel connected and have that awful floaty feeling in the arm. sure their mechanics save them to a degree and they still make balls (tho not as many), but they lack feel and speed control and the timing of their stroke is off leaving them with less cue power and a feeling like they are working too hard.
There is one thing at the heart of that connected feeling and especially the lack there of that leads to all those thing I mention above and I find most pool players arent even aware of what it is. At least my mid handicap golf students know what it is if not necessarily how to address it.
So that's what I and other good instructors with a high level understanding of biomechanics can do for students....not just identify common sources of problems, but also provide little tricks for how to address them as well as teach how to build a better setup with these things in mind so there is much less variability day to day. So like I said in my original statement on what a good instructor can do for a player, they can make the player consciously aware of things that they are doing or things that are naturally happening when they are 'on' so they can reproduce the conditions for being on more often. This can be in the form of specific little moves they make like Rory's imdex trigger, or it can be as simple as making the student aware of basic mechanical concepts which somehow are hard to find in the pool world. But dont fret, not for long. I spill the beans on a lot of obvious yet somehow little known mechanical 'secrets' (many of which are actually well known and widely applied in other sports) in my upcoming book, "Let YOUR Stroke Out".