One of my Appraisees isn't appraising this year - do they still need a Case?

They certainly do!

Each Case allows you to track an Appraisee's progress for that appraisal year so when it comes to revalidate them you will be able look back at the Cases to see why they may not have 5 completed appraisals in a given Revalidation cycle!

There is a different way of creating the Case in this instances so first of all pop to their Appraisee page.

Make sure you set the Working appraisal year to the current year and you should see the option to select No need for appraisal this year: 

In this next screen you can select the Reason not to allocate from the bullet point list, you can make any relevant Notes and then hit Save:

Once saved you will be taken back to their Appraisee page with the following message letting you know the Case has been marked as no need to allocate currently:

You will also see if you scroll down to their Appraisals section that a Case has been created and marked as Closed: (here is the reason you selected):

If you click on Case in that row and scroll to the bottom of that Case you will notice in the Audit Log that any Notes you entered in the No need to allocate section will appear as below: