  Gauge symmetries play a central role, both in the mathematical foundations as
well as the conceptual construction of modern (particle) physics theories.
However, it is yet unclear whether they form a necessary component of theories,
or whether they can be eliminated. It is also unclear whether they are merely
an auxiliary tool to simplify (and possibly localize) calculations or whether
they contain independent information. Therefore their status, both in physics
and philosophy of physics, remains to be fully clarified.
  In this overview we review the current state of affairs on both the
philosophy and the physics side. In particular, we focus on the circumstances
in which the restriction of gauge theories to gauge invariant information on an
observable level is warranted, using the Brout-Englert-Higgs theory as an
example of particular current importance. Finally, we determine a set of yet to
be answered questions to clarify the status of gauge symmetries.
