The oil life monitors in newer vehicles are governed by a specific algorithm in the programming that is determined more by the daily use experienced by the vehicle. Severe duty and normal operating conditions can be confusing. Normal operating conditions being longer trips where the vehicle is running at a consistent speed for longer mileage, say 25-50 mile average trips.
Severe duty can be defined as stop and go city driving, very short average trips of less than 10-20 miles per trip and times when the vehicle is being used in other than normal conditions, IE: off road adventures with varied higher RPM ranges.
Because of this, the oil life monitor has nothing to do with the actual viability of the oil. Especially with full synthetic oils like Mobile 1 and AMSOIL, you CAN actually (if you are using extended intervals utilizing UOA) simply reset the monitor and go further. I have and many of my AMSOIL customers have actually had to reset the monitors when oil analysis showed that the oil had not dropped in viscosity, TBN and had little to no contaminants.
Short answer? When using Mobile 1, AMSOIL or any other true full synthetic oil. If you are doing so with the intention of changing every 4000-7500 miles, you really have nothing to worry about at all unless there are extenuating circumstances that would cause the oil to fail.