Hitting your weight loss goal early.
If you hit your weight loss goal before your round is over, that's perfectly fine. In fact great job at hitting your goal!
If however you have more weight to lose, but you have already hit your goal, you should decide on whether you want to go lower or not.
Sometimes our goal is just an arbitrary number, which is fine, but once you achieve it ask yourself if you like the way you look and are content. If not, you can continue on.
Compare your results with your "before" picture so you realize how far you've come