Hunting camp October 2026: 8 people, 3 days. Service needed?

I run a hunting camp in Montana with seasonal crews. We have a week of rifle season coming up in October 2026. It's 8 people for 3 days, no alcohol, we cook over a fire. The ground is grassy and level, and a service truck can drive right up to the spot. I'm planning to rent a standard portable toilet. It won't get heavy use, maybe 20 trips a day total. I'm wondering if I need to schedule a service visit for pumping during those 3 days, or if the unit can sit unused without issue. Does a short rental like this always require mid-trip service, or can it wait until after?