How long does it take to ‘realign’ your spine?
How long it takes to return a spine to optimal performance depends on how long it has had the problem. The longer the joints have been restricted, the more the body and muscles adapt to the problem. If the dysfunction started recently, it can sometimes be rectified in one session. If it has been there for 20 years and the joints are degenerated it may well take more than 10 sessions.
The issue is that the length of time that you have had symptoms may not necessarily be a good indication of how long you have had dysfunction in the spinal movement.
The frequency of the sessions makes a difference too. (A good comparison is the frequency you go to the gym) If they are too spaced apart you do not add to the benefit of the last session.
Once they feel better, many of people decide to continue coming in regularly (eg. once a month) to keep their spine healthy because they feel so much better and want to keep it that way, but the decision is always up to you. Some people need maintenance care more than others. Contributing factors that determine this include stress (which causes muscle tension), the amount of degeneration in the joints, exercises levels, posture (sitting and standing), scoliosis, congenital variations in the shape of vertebrae and many other things.
If you want to reduce the number of sessions you need, talk to your chiropractor about what postures and positions tend to add to the problem and avoid those positions. (eg. Looking down at a phone or a laptop positioned on your stomach for hours) Exercise really helps too. The body loves movement—it helps to maintain the mobility of the joints between sessions, plus it increases the blood flow through muscles relaxing them.