There is some confusion about the difference between the astral plane and the spirit realm where beings inhabit after death of the physical body. According to the in-depth information in J.S.M. Ward's spiritualist books: “Gone West” and “A Subaltern in the Spirit Realm”, the astral plane is a realm close to, and interpenetrating the earth, where the recently dead go until their astral form disintegrates and they find themselves located in the spirit realm inhabiting a spirit body.
The astral body is said to a form, similar to the physical body, but more subtle and free in its movements. It is a step between the physical body and the spirit body, which is more subtle and free again, in comparison with the astral form. The astral body apparently has a limited lifespan that depends on a number of factors, including the age or vitality of the physical body when a person dies.
According to Wards work an old person’s astral body has a very short life span and when someone old dies their journey through the astral realm is brief. Younger deceased spend longer in the astral realm as their astral form lasts longer before it is shed and the soul then operates through the spirit form which is believed either immortal or at least extremely long lasting until that in turn is shed a more subtle form again is taken. Because those in astral form can more easily interact with the physical realm that those in the more subtle spirit body some souls attempt to extend the length of time they maintain their astral form. These beings are spiritually undeveloped and seek to continue the materialistic ways of their physical life. However, such a state cannot be maintained indefinitely and so such beings will eventually lose their astral form and either fall into the Hell realms or rise into the spiritual realms of light.
More detailed information on the astral plane can be found in “A Subaltern in Spirit Land” by J.S.M. Ward and more information on the spirit realms, particularly the Hell realms, can be found in “Gone West” by J.S.M Ward and A Wanderer in the Spirit Lands by Franchezzo among many others.