One way to look at it would be...if you brushed your teeth once, would you expect to have healthy and clean teeth the rest of your life? Why would we assume that we only needed to have our spine adjusted once and forever be cured of any damage or structural problems?
Trauma to your spine happens from the moment you are being born through the moment you die. Often this trauma goes uncared for an eventually becomes painful at which case most people take drugs to manage their pain. This does not fix the structural problem -- it only masks it.
Chiropractic is the only solution to joint and structural problems.
And often Chiropractics are only consulted after years and years of damage, drug use, and surgery...it will take time and commitment to achieve health “as near normal as possible”.