hey, Ram!
to the .oRg!! Good initial questions, you'll probably get a lot of varied answers as some of the responses depend on type of use and circumstances.
Chain/sprocket question is a monitored maintenance issue judged by a visual inspection of the sprockets and a physical measurement of the chain.
Shifting any manual transmission without the clutch is circumstantial but as far as the bike is concerned, under normal riding conditions use the clutch. A lot of people who compete in whatever form will shift clutchless but be forewarned this is hard on the transmission. So it depends on what you are willing to endure in maintenance and parts/replacement investments.
Pads and rotors are another monitored maintenance issue and life expectancy depends on your riding habits, ie: mainly front brake use, 'riding' the brake, mainly rear brake use (a no-no among more experienced riders!). If you are on top of your game, you'll eyeball your pads to determine rate of wear and replace before you allow metal to metal contact from a set of worn out pads. If you don't overheat your rotors through excessive/competition braking and keep the pads changed out with a good quality set before they wear out, you should see a long life from your rotors, again monitored through checking rotor thickness with a set of calipers.
My advice would be to invest in a good service manual for your bike. Should be available at your local parts house (NAPA, O'reilly's, Autozone, etc.). You may not use all the information available but this will help you become more familiar with what goes along with motorcycle ownership...it's just a little more than 'hop on baby, let's go!'
Good luck to you and again