If you belive more in math than in randomnes you should play martingale. What is the odds of red popping up yet another time...
50%
Math is the reason that you should NOT waste your time or money on a "Martingale System".
There is a right and a wrong way. Using free money they give you as a new member on a site is right. Using your own money is wrong.
Got 3 euros on a site and turned it into 1100 euros. Redrawing that and never going back to that site felt good...