Speed matters as much as the edge. A busy live table manages around forty spins an hour, while an automated wheel or an online game can run several times as many, and each spin charges the same percentage of whatever is staked. Whether roulette is worth playing depends on treating that cost as the price of entertainment: at a slow table a fixed budget lasts an evening, at a fast screen the same budget can be gone within minutes.
Roulette odds come straight from the wheel. On a European wheel there are thirty seven pockets, so the chance of landing on green is one in thirty seven, and on a double zero wheel one in thirty eight. Red and black each hold eighteen pockets, and neither color wins more often over time; a streak of one color says nothing about the next spin. The color rules are simple: zero counts as neither red nor black, so even money bets lose when it lands.
The best odds in roulette are on a single zero wheel, and better still under French rules. European roulette keeps an edge of about 2.7 percent; French tables add la partage, which gives back half the stake on even money bets whenever zero lands and so halves that edge on those bets. French layouts also take call bets placed by name, such as the neighbours bet on a number and the two either side of it on the wheel. Knowing how to play French roulette mostly means knowing these extra rules.