Based on its intended use and the size of the space, I would make the shelves adjustable. It is true that people don't change adjustments often, but I like to keep my options open.
Two days ago, my spouse and I just adjusted the shelves in my section of our wardrobe, where I store most of my clothes. I had not changed the shelf positions in 14 years, but it was nice to have that option.
If it were my own space, I would think about making sawtooth shelf supports. There is no practical reason. Shelf pin holes are easier and just as effective. The only reason I would use sawtooth supports is for the fun of making them and pride in workmanship. I like 'em.
See the attached photo with a closeup of a sawtooth support in our wardrobe. I have seen them used in closets and cabinets, too.