We would charge for- Excessive mounting holes (their wall was covered in picture hangers), holes larger that a quarter, different color, pet damage, smoke damage, anything that takes more than 1 coat of paint to cover.
Dirty walls or scuff marks is normal wear and tear to us...we are painting the apartment anyways. To us, if you nickle and dime move-out charges it reduces the chance the former resident and their 20+ close friends, 200+ social media friends will rent from you in the future. No sense in loosing future leases for a scuff mark.