I learned as soon as you cross the fix you report established and reconfirm
your altitude.

This makes most sense, because all ATC needs to know is that you are in the
right place at the right altitude. All the pretty stuff about entries and
timed legs etc only concerns our pride as pilots - as far as ATC is
concerned, if you can stay within the protected airspace (which is huge, for
GA planes) and maintain assigned altitude, the hold has done its job.

G Faris