  A wealth of X-ray and radio observations has revealed in the past decade a
growing diversity of neutron stars (NSs) with properties spanning orders of
magnitude in magnetic field strength and ages, and with emission processes
explained by a range of mechanisms dictating their radiation properties.
However, serious difficulties exist with the magneto-dipole model of isolated
neutron star fields and their inferred ages, such as a large range of observed
braking indices ($n$, with values often $<$3) and a mismatch between the
neutron star and associated supernova remnant (SNR) ages. This problem arises
primarily from the assumptions of a constant magnetic field with $n$=3, and an
initial spin period that is much smaller than the observed current period. It
has been suggested that a solution to this problem involves magnetic field
evolution, with some NSs having magnetic fields buried within the crust by
accretion of fall-back supernova material following their birth. In this work
we explore a parametric phenomenological model for magnetic field growth that
generalizes previous suggested field evolution functions, and apply it to a
variety of NSs with both secure SNR associations and known ages. We explore the
flexibility of the model by recovering the results of previous work on buried
magnetic fields in young neutron stars. Our model fits suggest that apparently
disparate classes of NSs may be related to one another through the
time-evolution of the magnetic field.
