This reports the condition of the circuits in the property, i.e. the wires and sockets in the walls, to ensure they are safe to use (i.e. it meets the requirements of BS7671). The report is centrally recorded so progress and history can be monitored.
There is a guidance note to the BS7671 standard which indicates that domestic properties should be tested every 10 years.
In the absence of any specific guidance for residential rental properties the prudent advice is to follow the five year inspection frequency for the higher risk HMO premises.
This assumes any issues identified by the EICR are fully addressed and any subsequent significant electrical installations are carried out by a qualified electrician, who would provide an appropriate certificate as an addition to EICR.
If you have an old fashioned fuseboard, the EICR will almost certainly say it needs upgrading to a modern distribution panel with trip switches RCD breaker switch.
Additionally where there are changes of tenants between EICRs there should be a check for obvious problems (broken sockets and light fittings) plus a manual test of any Residual Current Device (RCD) in the property. Where issues are found it is advisable to complete a Periodic Inspection Report, which tests the circuits for problems. The PIR produces a report but is not centrally recorded.