I have no idea how Predictive RAIM is viewed on complex aircraft such as Boeing and Airbus products, but on simple fixed-gear aircraft such as a Twin Otter, we just go to the PRAIM page and look.
The column on the left shows the RAIM prediction for 15 minutes before and after the expected approach time (this is taken from the FMS and is updated dynamically), and the column on the right is there to let you type in an alternate (CYVR is shown) and see if you will have adequate satellite coverage at the alternate.
It's not really necessary to look at this page, though, because if the RAIM prediction for the estimated approach time ever becomes unfavourable, the FMS will pop up a message advising the pilot.
Honeywell Primus Apex - Predictive RAIM Display
