Non-plugin hybrids don't
Non-plugin hybrids don't drain to zero unless something has gone badly wrong, so the battery will never be dead. You'll always have it to help at the start of a trip.
To be more specific, non-plugin hybrids always try to keep the battery at about 50%. I've never seen mine go under 25%. I have maxed it out through regenerative braking, but that's a different issue.