1 number has a probability of 1/37 for 0 and 1/38 for 00 roulette. A specific number coming back to back in 2 consecutive spins has 37 x 37 = 1369, so once every 1369 spins. But if we want to know the probability for any number coming back to back in 2 consecutive spins then we divide the probability of a specific number with the total of roulette numbers: 1369/37=37, thus equal to the chance of any specific coming once. Therefore we can take step further and consider any number coming twice in 2 spins in a row as one specific number. If we were betting for a repeat of such event then we would have to register any number coming twice in 2 spins and after hitting again to bet it since we are betting any number in paired hits. For example: 2,35,8,8 now we register number 8, from now on every time number 8 comes we'll bet it for its 2nd successive hit. The same would do with all numbers, considering the total expectation for having a couple of paired hits, from any number, it's equivalent to a single number repeating when we add every spun number until the one of them repeats. For example: 1 hits, bet 1, 23 hits, bet 1,23, 15 comes, bet 1,23,15...etc The first repeat cannot exceed the 24 unique numbers and this would be extremely rare to occur. Since with the coupled pair hits we are not betting every spin, neither more 1 number at a time, we need a way to calculate the maximum total of bets we have to lose before we win. By adding the numbers we register and are active for betting when the opportunity arises we can find the max total of bets we must place. 1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24= 300 bets, usually takes much less, about 80% the first coupled pair hits will happen within first 80 bets. The total of spins will be more because we are not betting every spin, how much more, if for bets is 300 max, it could reach approximately 600 spins the equivalent maximum. When the win eventually happens we don't have to start all over, just remove the first/older paired hits from the number which won and back, all older. 300 bets are still many but significantly less than how long a number could miss, however there are ways which indirectly can handle even 300 consecutive bets. I've created a fusion progression which won by betting 678 missing spins for number 22. So it can do only better with less duration.