By JOANNE PALMER
Many synagogues hire cantors for the High Holy Days.
That’s when so-called three-day-a-year Jews show up in shul, to join their more observant peers. It’s when synagogue buildings are stuffed full of people, clergy prepare their sermons and messages and melodies, professional and lay leaders puzzle out security and logistics, and in general the community shows itself off to its members and to the outside world.