Many will dismiss outright ability to make good returns on your investment through medium of sports betting. It is not really surprising as betting is hard work, solitary, and you have to grind out thousands of bets to get your returns. Of course to many members of society - betting also carries a great big "loser" tag. This is not without justification since vast majority of sports bettors do lose. I would, however, estimate that percentage of "losers" would be equally high in world of stock trading and investment markets if you considered those individuals who entered that environment without necessary experience. Most people trust their savings and investment income to experts and no doubt if betting public trusted their income to 1% or 2% of betting experts who made a profit - loser label might become less sticky.
So what kind of returns can you expect? Anywhere between 18% and 22% on betting turnover (that money actually put through sportsbooks) annually. Of course this could vary greatly - years of 30% and 13% would also be possible. The laws of probability defy accurate annual estimates.
You will notice that I have not stated losing years - this is because they are rare - I have experienced one in my life time, my first. I am always aware of possibility but I am confident I will never experience one again - partly because of numerous hedging methods now available on sports betting exchanges. I wonder how many young people on Wall Street today can confidently say they will only have one losing year? There may be a handful, those engaging in arbitrage and those experienced in 'selling' as well as 'buying' market - but there won't be many.
So do sportsbooks close accounts if you are a winning player? Well curiously answer is 'yes'. I say curiously because if book is doing its job properly, it is taking action from both sides of line (odds on event) and simply taking commission in middle. The sportsbook makes its money whatever result - they are merely commission-takers. Winning bettors do not win money from a sportsbook, they win money from other losing players. I guess some books simply do not like winners - but many manage action well and allow big bets. Big bets means big turnover, big turnover means big profits.