I hate to derail... but the amount of effort you spend should be dependent on your level of skill, temperament for grinding, and poker goals. Poker goals and skills are similar and feed into one another.
TL;DRs need not spam/troll/respond
The lower your skill the less hours you should invest playing and more hours you should invest in increasing your winrate through HHs/studying/+LiveEV moves.
Everyone has a certain point where no matter how much they are crushing or stuck they just get burnt out. It could be burnout for a few hours or a lifetime, regardless of the recharge period you should wind back the hours anytime you run into this feeling in a given month.
A lot of poker pros are big winners and their stakes and while improving their game will always up their winrate, their goals or huge ego restrict them from playing higher stakes, thus their returns from studying are marginal. The more keen you are to have the ability to move up stakes the more you should invest time into improving your game and decrease your live-play hours.
The best part of being a poker pro is the freedom to work when you want & have extra $. You're the boss/entrepreneur/manager and ultimately only you can set the pace which will dictate your success/failures, everyone experiences a unique journey and there is no sacred path in the non-standard career path of a cardplayer.
One should
leverage your extra time to increase your happiness inside & outside the game while maximizing the potential and number your non-poker options because the game could fizzle out with new legislation or a rapid decline in many Americans wealth (i.e. stock crash).
Everyone says they have an exit plan, but if gambling become illegal today, where would you earn your salary tomorrow (Walmart/Wallstreet/Panhandling/Chippendales)? What are you doing with the extra money that you have laying around the house/in mattress/loaned to stakee is a pandora's box that I won't bother addressing here but is very important regardless.