The single number that matters is daily on-site people, not headcount on the payroll. A 90-person office running three days a week hybrid behaves like a 50-person site. A 40-person warehouse working two shifts behaves like a 70-person site. As a rule of thumb, around 30 people through the space on a normal day supports a standalone drink or combination machine, and roughly 60 supports a snack machine and a chilled bank side by side.
Beyond people, we look at three practical things: is there a standard 10-amp power point within roughly two metres of the intended wall, can a two-person crew get a 700kg pallet-jacked machine from the loading dock to that wall without a step, and is the machine visible from where people already walk? Sites that fail on visibility fail commercially far more often than sites that fail on numbers. A machine tucked in a back corridor sells around a third of what the same machine sells beside a lift lobby or a crib room door.
Where a site is genuinely too small on its own, we still have options — a shared install across neighbouring tenancies in the same building, a smaller smart cooler instead of a full combo, or a scheduled review once headcount grows.