Depends on the switch type. MX switches can do with some breaking in, as do buckling springs. Alps really not.
Cherry switches need to be broken in until they're nearly at the switch limit, or around 20 years.

Although apparently the newer Cherry MX switches have been updated and are smoother, at least for Black and possibly Brown stems.
I'm hoping this is the case as I find the sound of MX is much nicer than Gaterons.