The guideline from scientists is that if you decide to use it you need to nearly overdose the patient on it, despite that that is not necessary to cure them. Doing that is much more expensive (not that much more expensive really, it just looks impressive in % and presumably in excel sheets), but fights resistance.

I'm skeptical of this often cited claim. The more you use it the greater the evolutionary pressure you place and the more you force evolved resistance. If you overuse an antibiotic, you kill off all of the bacteria that could compete with the resistant strains, thus strongly promoting resistance.

I posit that like with all other evolutionary pressures, reducing the pressure is the right approach.