  Measurements of neutron-star macrophysical properties thanks to
multimessenger observations offer the possibility to constrain the properties
of nuclear matter. Indeed cold and dense matter as found inside neutron stars,
in particular in their core, is not accessible to terrestrial laboratories.We
investigate the consequences of using equations of state that employ models for
the core and the crust that are not calculated consistently on the neutron-star
macrophysical properties, on some of the so-called universal relations and on
the constraints obtained from gravitational-wave observations. We use various
treatments found in the literature to connect together nonconsistent core and
crust equations of state. We then compute the mass, the radius, the tidal
deformability, and the moment of inertia for each model. Finally, we assess the
discrepancies in the neutron-star macrophysical properties obtained when
consistent models for the whole star and nonconsistent ones are employed. The
use of crust models nonconsistent with the core introduces an error on the
macrophysical parameters which can be as large as the estimated accuracy of
current and next generation telescopes. The precision of some of the universal
relations reported in the literature is found to be overestimated. We confirm
that the equation of the crust has limited influence on the macrophysical
properties. The discrepancy between results obtained for a fully consistent
equation of state and a nonconsistent one can be reduced if one connects the
core and the crust models at baryon densities around 0.08-0.1 fm$^{-3}$. The
equation of the crust cannot be probed with current multimessenger observations
and near-future ones.
