Annual appraisals are a good idea
There's no requirement that a clerk's performance is reviewed regularly - which is why it often isn't done at all.
But the Governance Handbook states that all clerks are governance professionals and crucial to the board's effective operation (page 46). Because the clerk's skills are so vital, you're expected to set demanding standards and then pay a salary commensurate to the level of service you expect your clerk to deliver. In order to do this, you should conduct regular appraisals where you:
If you're introducing an appraisal process for the first time, be sure you meet with your clerk to explain why this is happening now and why you think it's important. It should be approached as a way to encourage and reward professional development and