Since most of the matches I watch involve India, I dont have a problem of watching all sessions if the timings are good. Till few months back, I used to watch test matches the whole night (tests played in India start at 10:30pm and end up 6am for me). But now I have decided not to lose too much of sleep because my health has been affecting me. For India tests, I watch a minimum of one session and as much as the 2nd session possible depending on when I decide to go to sleep. If tests are played in Australia, New Zealand, its very easy coz it starts in the evening and ends up at around 2am (I normally sleep by 3am on average everyday).