You won’t often need either. If creases happen, cool iron on the lowest setting, and never iron the waistband, printed labels, or mesh panels. Steam from a short hang in a steamy bathroom often does the trick without contact heat.
For dryers: line drying is best for longevity. If you must tumble, choose low heat / delicate, remove promptly, and don’t overdry. Avoid dryer sheets (they act like softener). These habits keep the handfeel silky, the mesh breathable, and the waistband snappy—so your pair stays a first pick long after wash 20.