a property rewired is expensive and disruptive, so we often put up with the wiring we’ve inherited when we move and forget about getting it sorted.
Unless the sockets, light switches and flexes are obviously old, it can be hard to tell the age of the wiring. A good place to start is the fuse box. If it has rewirable fuses, for example, it should probably be replaced because modern fuse boxes don’t use fuse wire.
Other signs of old wiring include sockets with burn marks, sockets mounted on skirting boards, and surfacemounted cables.