Is it necessary now to include access dates?

Hi, EE...

I'm confused...  In reading some responses to another thread here, I saw that there were no access dates included in a citation to online images at a website.  However, when I go to the new Evidence Explained (specifically 11.39 State-level Certificates), access dates are included in the citation.  Is there a hard-and-fast rule, or is this personal preference?