The basic fact
A casino is not a job or an investment
Casino games are designed so the operator has a mathematical advantage over time. The exact edge varies by game and rules, but it means the expected long-term result favours the house—not the player.
A previous spin does not make the next spin due to win. A losing streak does not create credit with a game, and a recent win does not prove that a system works. Increasing the stake only increases the amount exposed to the next uncertain result.
Before gambling, assume the entire stake may be lost. If losing that amount would affect a bill, a savings goal or another person, it is not disposable money.