In recent years the idea that dark matter is composed by primordial black holes instead of particles regained interest. Testing the viability of this dark matter candidate requires several steps: determining their maximum abundance and if they can constitute the totality of dark matter, developing detection strategies and understanding how these objects formed in the Early Universe. In this talk I will cover some aspects of each of these topics. First I will show with worked examples what are the limitations in existing constraints on primordial black hole abundance, then I will present a possible way to detect them in the Late Universe and finally I will discuss what we can learn about their formation mechanism if we detect even a single primordial black hole.