My first decision to ‘turn pro’ was made on the basis of no alternative source of income and weighted by the influence of the Robert De Niro character in the film Casino. A few disastrous months later I returned to work. But no matter however carefully you plan your approach to this business, I think you have to be prepared for periods of abject failure.

If you are thinking about betting for a living it is likely to be on the basis of some creative and profitable analysis of the sport and markets you are interested in. But your decision to do this full-time has to be based on a much more mundane calculus. You need to work out if you can earn a living from your edge. So, you may well have a betting system that gives you value of 5% with cast- iron certainty (p-value to multiple zeros), but unless you can find enough opportunities to get bets on and you have enough capital to cover losing runs, you won’t make enough to pay the rent, or you’ll go broke in the short run.

Imagine you have found your 5% value by betting on the away team in a Premier League match when the first letter of the away team is ‘M’. And you know there are two teams in the league matching the criteria so that gives you 38 betting opportunities per season, or per calendar year. Next, you need to work out how much money you need to survive. You might work out you can live off your last pay check by spending £4.37 per day, and we can all do that for about 4 days, but after about that length of time it is going to get boring. Being more realistic if you live outside London and you don’t have dependents you might work out you need a minimum of £2,000 pcm or £24,000 pa.

So you need to generate at least £24,000 from your 38 bets, which means £632 per bet and an average bet size of £12,632 (632 = 5% of your stake). Also, you need to calculate the probability of losing all of your capital in a losing run. You could do this in a number of ways mathematically or empirically from your ‘what-if’ analysis of previous betting opportunities. On our ‘M’ betting strategy you might decide all results dating back to the first Premier League season are valid, so you have 20 seasons worth of results with, say, an average of 38 bets per year, giving you 760 bets. If you plot the results of these bets to a unit stake you will see your increase in profit, but you will also see long periods where you have lost money. If you calculate the highest number of units lost between a high point and a low point to the right it of it on your graph, you have the worst case scenario in 20 seasons. If you multiply this value by your £12,632 you can see how much it will cost you.

This should be a sobering statistic and you should want to give up at his point, especially as there is no guarantee that your first season won’t give you a run of results worse than in the first 20 seasons!  Even with a betting strategy on events where you are likely to get your bets matched, where you have an edge that is higher than you are ever likely to find in reality, the bankroll requirement means you can’t make enough to live off this.

However, if you could find bets with lower value that occurred more frequently you have a much better opportunity. For example, if you found value in betting on the away side whose name began with M in all football fixtures across the world, then you might be able to bet 4 times per day (1460 bets pa).

Looking to make £24,000 pa, you need only make £17 per bet. If your expected value per bet is as low as one half of 1% then you need to stake £3,296 per bet, and if you can find value of 1.5% then you need to stake as little as £1,099 per bet.  This result is somewhat counterintuitive, opportunities with a quotidian expected value form the basis of a profitable betting strategy, whereas a real zinger of a theory might prove to be very hard to fund.

However, the difficulty with implementing a strategy that relies on 4 bets per day is the effort required to find and place those bets every day. It will be a much more complicated strategy than betting on ‘M’, so if you are betting manually you will need to factor missed days into your expected profits, and if you are going to use an automated system you need to think about setting that up as an expense. Either way, the cost of error, bets missed and not accepted will be much higher than you are likely to anticipate at the outset.

Assuming you have a watertight analysis at the outset you will make mistakes in executing bets and find that prices advertised aren’t always available. But it is more likely that your system will need fine-tuning when you start trading, so it may be months (and a great deal of expense) before you start to see your bets making profit. And there is no guarantee that you will recoup these costs in the long run.

The life of a pro trader can therefore be stressful, but if you can carefully and astutely manage your bankroll alongside your trading strategy, the monetary and lifestyle rewards can be significant.