  In this paper we study the phase of self-similar solutions to general
Nonlinear Schr\"odinger equations. From this analysis we gain insight on the
dynamics of nontrivial solutions and a deeper understanding of the way
collective coordinate methods work. We also find general evolution equations
for the most relevant dynamical parameter $w(t)$ corresponding to the width of
the solution. These equations are exact for self-similar solutions and provide
a shortcut to find approximate evolution equations for the width of
non-self-similar solutions similar to those of collective coordinate methods.
