Ask HN: Competition - market validation or reason not to execute on an idea?

I've got an idea for an app in the recipe/grocery list/meal planning space that I've been prototyping as a side project. Right now I see two main competitors as ven.io and eMeals in the space, but I think there's still a lot of room for the market to grow with the right execution, but I don't have any factual data to back up that hunch.

What metrics do you guys look at to decide whether or not existing competition is validation of the problem or whether the market is saturated with competition and to pursue another idea?