If you knew which number or numbers were most likely to come up in roulette, you would be able to win more money than you lose. By betting on the numbers that are more likely to appear, you stand a much better chance of winning money over the long run. In fact, you can almost guarantee that you will always be walking away with more money than you started with.
The question is however, which number or numbers have a greater chance of appearing than the others?
Unfortunately for those of you looking for a definitive answer, I'm afraid I'm going to have to disappoint you. Roulette tables have been designed to keep them as fair as possible, so that each number has the same chance of the ball landing upon it as the next. So even though people may have their lucky numbers, in the long run they are going to show up the same number of times as all the other numbers.
Despite this, there is always the small probability that a roulette wheel may have some mechanical imperfection which will disrupt the probability distribution of the numbers. If the wheel is not properly weighed and crafted, it may mean that the ball will fall into some numbers more frequently than it should, resulting in a higher probability of that particular number or set of numbers appearing.
In the past, gamblers such as Joseph Jaggers have exploited these imperfections and walked away from the casinos winning thousans from day to day. However, casinos are very quick to spot when there may be a problem, and so it is not long before the wheels are repaired to prevent players from winning more money than they should.
In modern casinos, you would be very lucky to find a wheel that is not (or nearly) perfected when it comes to randomly selecting numbers. You can always give it a try to catch these imperfections, but even if you did get lucky and spot one, you would not have long to try and win as much money as you could. So I'm sorry to tell all you people looking to win some money this ... but all the numbers on a roulette wheel have an equal chance of appearing.
At the end of the day, it is going to be very difficult to exploit a roulette wheel, and so it is best played for its entertainment value. If you can win some money while doing so, then all the better! There are a number of strategies that you can try to help give yourself a chance of winning more money than you lose, which are much better than trying to find those minute imperfections.