Does the Soul Take a New Body in One Year?

Does the soul take a new body in one year? Does it take ten years? How long
does one live upon the subtler planes before reappearing on the earth plane?

Swami Sivananda: There is no definite period of time in this matter. In main, two factors decide this issue, viz., the nature of the individual Karma and the last impression before death. It may vary from hundreds of years to a few months even. Those that work out some of their Karmas in other planes in subtler regions take a considerable time before entering a fresh body. The interval is very long, for a year of the earth period passes off as a single day on the celestial plane. There is an instance cited where, seeing the amazement and admiration of foreign tourists at the imposing ruins of certain ancient monuments, a saint present in the vicinity remarked that some of those people had fashioned those monuments centuries ago. 

A very sensual individual with strong craving or one with intense attachment sometimes is reborn quickly. Also in cases where life is cut short by a violent death or a sudden unexpected accident, the Jiva resumes the thread very soon. Usually, in such cases of immediate rebirth, the Jiva often remembers many of the events of its previous life. It recognizes its former relatives and friends and identifies its old home and familiar objects. This sometimes leads to very queer developments. There are some instances where a murdered person, being reborn, has declared the manner of his death and revealed the identity of the killer in the recent past. But such cases of immediate rebirth are not common.

Generally, for an average individual, the interval between death and rebirth happens to be a considerable period measured in terms of earth time. Persons who have done much good Karma spend a great deal of time on the Daivic plane before being born again. Great souls, spiritually advanced persons, wait for a long time before reincarnating.

(pg. 63, May I Answer That by Swami Sivananda)