My general rule : don’t snack. It is much easier to eat junk food when snacking. We also dismiss easily calories from snack but they easily add up. It is better to sit down with others and take a significant and balanced meal.
There are cases where snacking is ok. Endurance & strenuous exercise is a good case. Missing breakfast or a meal is another case. Eating something to prevent hypoglycemia or decrease effects of strong alcohol are other good cases.