Asteroid families are the result of past collisions between asteroids and they have always been identified as groups of asteroids sharing the same dynamical properties. Once a family is identified using the proper elements (Knezevic & Milani 2003) and clustering methods, we can compute the time of the initial collision (age of the family) taking into account the presence of non-gravitational perturbations, like the Yarkovsky effect (Spoto et al. 2015). The current classification of asteroid families includes more than 120 families (Milani et al. 2019), with ages ranging from a few millions years to 2 Gy. Asteroid families thus represents a powerful tool to understand the chronological history of our Solar System, and to find answers to what happened during the early phases of its formation. Our current knowledge is still incomplete and biased. We know that the clustering methods used until now are not enough to detect very young or very old families, and that a proper description of the Main Belt can only be obtained combining physical and dynamical properties of asteroid families. Thus the questions: How many families have not yet been detected? Are our ages accurate enough to obtain a real chronology of the Solar System? How can we use very old families to detect the primordial asteroids in the Main Belt? I will present the state of the art on asteroid families, including the recent results obtained in the search for answers to the previous questions. I will also focus my attention on the main limitations we have experienced and how they may be overcome in the light of all the new and amazing observations coming from the ESA Gaia mission and the Vera Rubin/LSST telescope.