Depends on what you are using it for.
RNP approach requires a RAIM check/prediction prior to dispatch to show availability. If the RAIM prediction for the approach is not sufficient for the RNP level prior to dispath, it cannot be used in the flight plan.
The pilot may also be required to perform a RAIM check enroute, depending on the RNP level at the final
There is enroute RAIM prediction as well, but with the RNP levels, it usually not an issue.
The system RAIM is always working, giving you the actual vs needed HIL/HPA levels, and will warn when the actual is greater than the required.
The WAAS check is a little different, as the WAAS prediction gives the geographic area of the RNP level, such as RNP 0.3, with the HPL, and the LPV percentage coverage.
RAIM/WAAS Check