The Wizard skill, "Familiar", summons a small helper that helps you attack enemies and cannot be hit. There doesn't seem to be a spell duration on it (no icon indicator as far as I can tell), but I have noticed at times that it would disappear and I would have to re-cast it. Beyond the obvious situation of dying causing it to disappear, in what other situations would I have to re-summon the Familiar? Does using a Waypoint or a Town Portal cause it to disappear? Or is there an actual duration to the spell involved?
Do you not have advanced tool tips turned on?
Familiar has a duration of 5 minutes.