Several factors come into play when you plan for your retirement. Your age, longevity, and the returns that you will earn from your retirement portfolio are just a few. In some form or fashion, all of those can play into your target retirement age.
But one frequently overlooked factor is the day that you will stop working. You may think that you will keep working until you are 70. Nevertheless, this is often an overestimation of how long you will stay in the workforce.
The fact is that you will probably not continue to work for as long as you think you will. That might be due either to health factors or the need to care for parents (or maybe other elderly family members).
This factor can substantially impact your retirement plans by either forcing you to forego retirement goals such as traveling and hobbies or live a significantly diminished lifestyle.