A number can go for deep sleep for any amount of spins, some say 600, others mention 800-900 times or even more. In my opinion it is really worthless to bet on such sleeper.
Other way to look at is, one could focus on what is the longest interval for any number not to repeat immediately? In Roulette a number repeating immediately is quite common.
I did one such test over 2 million spins, found that an immediate repeater would not come for 460 spins. If you have a method to make benefit of this statistic let us know.
It is easier to construct such a sequence by just removing all immediate repeaters for 460 spins.