No one who claims to be normal human being without super(studies)power can study CA subjects for generally more than 10 hours & in extreme cases 14 hours.
What matters is what you study and how well you study it along with very well rotation being ensured.
Dont listent to others as those who dont do talk a lot and those who do dont talk.
If you will study too much forceably 4 long period you wil ge fatigue just before examination or even during examination &you wil not be able to perform.
It is more than sufficient if you study 'in depth' particular topics for about 6 hours per day upto 6 months before examination & then for three months 8 hours per day revise fast & try to hold whole course in your memory & then for last 3 months revise whole course again with exam specific weightage on atleast 4 past RTPs & 8 pasts SAs & all PMs well covered & also grade problems according to difficult level while indepth studies so that you can revise better & faster in last 3 months.
Its more about how well you manage the course that will make you successful.