How Do You Pick the Right App Development Agency for Your Project

I’ve been exploring options for an app development agency to help bring my mobile app idea to life, and it’s been a bit overwhelming. Some agencies seem very skilled, while others don’t seem to fully understand what I’m trying to build. I’m curious do you usually go with bigger agencies, or do smaller teams sometimes deliver better results? For those who’ve worked on apps before, how do you figure out which agency is the right fit?