Picture from Google
I'm in the business of making orthotics, but custom and non-custom. Yet, there is a huge population who will probably never need them. Even those who pronate more than usual, in many cases, can live their lives just fine without ever needing the extra support.
On top of that, general foot fatigue will always set in if you're standing on your feet for hours at a time. I even find myself constantly shifting positions, transferring weight between feet so my knees and back can spread gravity across more bones and muscles.
When you're running around, or pulling that extra shift as a waiter or construction worker, your feet will get tired. So will your whole body. But still, you may not need orthotics.
But when do you?
According to an article newsletter I read by one of the leading biomechanic podiatrists, Kevin Kirby, he had termed the phrase "Tissue Stress Theory." In this article, Dr. Kirby describes how a neutral stance may not always be best for a patient. In fact, he encourages either pronation or supination, ultimately stating that the amount of deviation from 0 degrees from an upright position is just fine--what doctors should be looking for instead is the amount of stress the tendons/muscles/connecting tissue undergo.
There's a good chance also that you may need orthotics down the road, and that your tissues can simply endure a lot of stress. A great test is to look at how much wearing away at the soles of your shoes you are causing.
Does the inside or outside of the shoe wear out considerably faster than the other side? Or does it wear away evenly across the outside (lateral) side of the shoe? Everyone's heel strike is generally slightly lateral. However, excessive wear and tear is a good sign you're over stressing your tissue. You are your own best doctor. If you feel that your feet hurt more than just muscle ache from a long day, try an orthotic. See if it helps. Try to avoid a Dr. Scholls, but look at some of the one's I recommended a few posts before.