Well it's pretty cliche to say, "Study your hand histories, and you will find your leaks."
Cause if you dont know how to play perfect poker to begain with, then how do you know if your are actually filling leaks? Thus what is the point in studying? Yea, it's easy to go back and see where you punted off chips on a bad
bluff, or maybe lost some value, because you saw something that really wasnt there.
The evolution of the game is key. What was a winning play 5 years ago. (In Some situations) is actually a break even play now, and what was a losing play 5 years ago is actually a EV+ play today....
This is why it's very important to find a coach/community/study groups. And meet weekly with them. I have a coach that I meet with in my study group weekly. We have a discord set up the send hand reviews, and we are always bouncing ideas off eachother to help improve our game. Do I pay them? Yea, I do. Not much though. $50 a month of 15% of my profits. Whatever is higher. But this is how we all get better....
I have my coach, he holds his group on Wed. Nights.... so we all get together and go over hands, and he offers suggestions, and gets insights on how all would play hands. Typically there are about 4-7 of us in that group every week....
Now on Tuseday night "My Coach" has his study group with "His Coach" and peers.... that's where he bounces ideas off of the people at his level, and the coach that plays at an even higher level then him. This is where he learns the evolution of the game, and passes it along to us....
Then his coach has coaches.... and so on.... you are never "too good" to have a coach. Hell even Daniel Negreanu has coaches.
So then you ask, "Well JB, what do you do to help people below you?"
I Say, "well since my BR is low due to the fact I had to withdraw 75% of it last year. I've had to start from the bottom again myself. Thus I really dont have a group. Granted I'm trying to get one started for players on Monday nights. That's why I get on here and try and offer a little advice from time to time for anyone that sees it."
I know that's a lot to take it, so to answer you actual question. Lol. I would say it's less about actually spending the time to study, but knowing how to study. And what to look for, and how to transform your game to move up stakes. Cause you might find a way that works at your current stake, but wont work at the higher stakes. (That's what happen to me)
I hope that helped anwser your question. If you have any other questions please feel free to send me a message.