We review here the multiplicity properties of ultracool dwarfs (spectral type later than M6) observed in three different environments and at three different ages: in the field, where the objects are relatively old (1-5 Gyrs) and isolated, in the Pleiades young (˜120 Myr) open cluster, and in the young (˜5 Myr) Upper Scorpius OB association (USco). While the field and Pleiades populations seem to have very similar properties, the preliminary results obtained in USco might show significant differences. If confirmed, it would mean that the phenomena responsible for the ``final'' properties of ultracool dwarfs multiplicity are still at work at the age of USco, but are already over at the age of the Pleiades.