Although not a legal requirement in your own house, an EICR is the best way to ensure the electrical safety of your home. When selling your property, a satisfactory EICR can be a selling point.
Landlords are required to test the electrical safety of their rental properties every 5 years or each time the tenants change.
Commercial properties follow different regulations and instead it will be down to your insurance providers and the type of business to determine the frequency of the EICR.