I'm always wondering how an addiction starts for everyone because I'm sure that we have different experiences with gambling that will contribute to an addiction. Frequently gambling is one of the most common reasons why a player gets addicted. So I'm thinking before you become involved in frequent gambling behaviour what is the sign that you notice that you are doing when you gamble?
Mine is I always check my wallet balance to check my current profit then place a small bet without any reason just to gamble and increase my profit. This makes me gamble frequently because of the greediness to earn more until I become hooked and worst is when I lose everything on a bad day.
Frequency of it can be a sign but it can be also a sign of handling your finances so that you afford to play more frequently. Not all addicts are same and there are very different ways people get addicted. Some aren't causing much harm, so people ignore it as a normal behavior, and some of them have devastating effects. You can be addicted and not gambling because you just can't afford it anymore and there's nothing in your budget to take cash for gambing. And then at the pay day you can spend it all immediately.
However if you find a pattern or a sign in your behaviour that tells you, that you might be addicted, don't ignore it. You don't immediately have to act on it if you are doing ok, but keep that as a data point for your mind, when you are reflecting your behavior later on. Then you can remember that you have suspected this before.