There are really no "normal" riding regimes where it makes sense to turn traction control off. (You may get some argument from old-timers, but if you do not know what it does or why you would turn it on or off, just leave it on and forget it -- it is good stuff.) If you are wondering about its effect, you should buy some track and instructor time so it can be demonstrated in a controlled learning environment.
If your brake lever has a very long travel before the brakes engage, you should probably take it in for service. There is a chance that you have gotten air into the system and this needs to be addressed by someone who understands the problem.