  We use the Bayesian approach to write the posterior probability density for
the three-dimensional velocity of a pulsar and for its kinematic age. As a
prior, we use the bimodal velocity distribution found in a recent article by
Verbunt, Igoshev & Cator (2017). When we compare the kinematic ages with
spin-down ages, we find that in general, they agree with each other. In
particular, maximum likelihood analysis sets the lower limit for the
exponential magnetic field decay timescale at $8$ Myr with a slight preference
of $t_\mathrm{dec} \approx 12$ Myr and compatible with no decay at all. One of
the objects in the study, pulsar B0950+08 has kinematic and cooling ages
$\approx 2$ Myr which is in strong contradiction with its spin-down age
$\tau\approx 17$ Myr. The 68 per cent credible range for the kinematic age is
1.2--8.0 Myr. We conclude that the most probable explanation for this
contradiction is a combination of magnetic field decay and long initial period.
Further timing, UV and X-ray observations of B0950+08 are required to constrain
its origin and evolution better.
