I have seen many many people try to do their own thing over the years and I am convinced that there are actually not too many people who can be consistently successful at it. The success does not seem to lie in the method so much as the discipline. I think the most common thing I have seen is for inexperienced traders to lose discipline when thier "bulletproof" method has a few consecutve losses. No matter how much testing and paper trading and pledges to stick to it occured before, real losses can really throw all that into the dustbin and so begins the path to failure. The reality is plan the trade and trade the plan, no exceptions.
I think 15% per month on average is a reasonable amount for a succesful day trader to acheieve. Do the math. If you have enough capital, it's a very nice living Almost all who try fail.
It helps my pension. I wouldn't do it as a fulltime job, though, it's too much of a responsibility for a family man and, I admit, when I am at it I want to be left alone, to the extent of leaving my food on the table, if necessary.
What is worse, though, IMO, is coming home in the evening and plugging into the Dow.