Poltergeist disturbances are of fairly short duration. Perhaps a couple of months. Hauntings can go on for years.
9 seconds sound clip from the Poltergeist (1982) movie soundboard.
You can hear this line at 00:46:54 in the Blu-ray version of the movie.
Quote context
[...]
- Gotta be quicker than that around here.
- It's electrical. You can smell the charge.
- You were saying about poltergeists?
- Poltergeists are usually associated with an individual.
- Hauntings seem to be connected with an area. A house, usually.
- Are you telling me that all of this could just suddenly end at any time?
- Yes, it could. Unless it's a haunting.
- But hauntings don't usually revolve around living people.
- Then we don't have much time because my daughter is alive somewhere inside this house.
[...]