I begin teaching my students 1 finger per fret. My goal is to get them using all 4 fingers as often as possible. For example, (for my beginners) a C Major scale in first position would be finger 3 on the root, open D, finger 2 on the E, 3 on the F, open G, finger 1 on the A, finger 3 on the B, and finger 4 on the octave C. Also, if my student has small hands, I encourage a subtle position shift to make it easier to use finger 3. When my students hit the intermediate stage, they sometimes naturally start to alter their fingering to more of a 1-2-4. As I notice what they're doing, I make them aware and tell them it's okay, but as they transition, they need to use consistency. Let's face it: Fingering is subjective, and after you've played a while you naturally develop idiosyncracies. As long as you're being logical, not doing something painful, and being consistent, I think most of us turn into pretty good musicians despite the differences in fingering approach.