I know that different sizes are sold but when should I be using a taller vs. shorter tee. Is there an appropriate time or is it just preference?
I had once used longer tees when using a driver, but I hardly use longer tees anymore for this purpose.
I used longer tees to make contact with the ball on the upswing of my tee shots using a driver. The driver is the hardest club to hit, and making contact with the ball on the upswing promotes distance. Also, contact is typically imminent using a driver off the tee due to its typically larger clubface compared to other clubs. I no longer use longer tees due to accuracy. Instead, I use the length of shorter tees for this purpose.
I use shorter tees (usually, with only the top tip of the tee exposed) to make contact with the ball on the apex of the downswing of my tee shots using woods, hybrids, and irons. These clubs are not as hard to hit as the driver, and making contact with the ball on the apex of the downswing promotes solid contact. This is called "hitting down" on the ball, and typically, especially with irons, a divot would be made on these shots, on or off the tee.
In my experience, I have not found this to be preferential as I do not know anyone who makes contact with the ball on the upswing, on or off the tee, using woods, hybrids, or irons. In addition, it is rarely feasible to make contact with the ball on the upswing of non-tee shots.