Too much studying might lead to burning out and running out of gas I guess?
I think there’s an optimal level of studying enough to pass the exam and moving beyond that level adds little value which I’m not sure if worth the additional time and energy.
More time and energy spent studying means less time and energy spent with family and friends and doing other endeavors to lessen the stress.
I study hard but I still make sure that I enjoy life once in a while with my loved ones. 
I live in Chicago. Awesome city in the summer and fall, but terrible in the winter and spring. It’s a lot easier to study when it’s 10 degrees F outside, and it’s dark at 5pm every night than compared to when the city is alive.
Anyhow, the way I see it…400-500 hours should be a sufficient amount of time to study. If you’re dilligent about studying, you can do 80 hours a month beginning in December and you should be adequately prepared. Six months of 80 hours/month is 480 hours of total study time. I agree it’s good to start early, though. Something may come up in March/April/May that may reduce your ability to study.
Don’t want to sit for this thing twice, so it’s better being overprepared than underprepared. I plan on hitting this stuff late October/early Novemeber.
I stopped thinking about hours and just pushed through the CFAI material. Its been a long road for me. I would have failed again if I hadnt taken a Kaplan course this time. I had all the wrong approach in the am and wasted too much time on stuff I was struggling with anyways. Id say I put in the most hours this time around than I did for any other exam, but that was just a function of being thorough.
I was going to start in January but I found out yesterday that not only is my wife due May 4th with our first child, but she is also pregnant with twins. I should have started last week.
F*** that Band 10 this year continues to sting.
This is my first time at L3. I will start by mid Oct. As of now cant say about the optimal number of hours for me. I will start with CFAI and keep Kaplan as a standby for topics tht doest not require lengthy explanation. I plan to do one thorough reading and spend more time doing test papers and questions. Feb and March is going to be busy months for me. April onwards should be able to take out sufficient time.
Cheers!!
“Prepare for the worst and hope for the best”