How Often Should You Restock a Vending Machine?

An out-of-stock slot costs more than the vends you missed.

The direct loss is obvious. The compounding losses are what damage the business:

• Customers stop checking. Someone who finds their item gone twice stops looking. You've lost the habit, not just the sale — and habit is most of vending revenue.
• The location loses confidence. An empty machine in a lobby reflects on the business hosting it. This is the single most common reason a location starts listening to your competitors, and it's exactly the opening other operators look for.
• Perceived reliability drops faster than it recovers. Getting back to "the machine's always stocked" takes far longer than losing it did.

So when you're weighing a possibly-unnecessary trip against the risk of running dry, the empty slot is usually the more expensive option. Err toward servicing.

Use these to begin, then correct with real data — every location will surprise you in one direction or the other.

Adjust for two things the table can't see:

Season. A site that's comfortable at fourteen days in November may run dry in eight in July. Cold-drink demand is the usual culprit. Plan summer capacity deliberately.

Shift patterns. A warehouse running two or three shifts consumes at two or three times the rate of the same headcount on one shift. Ask about shifts when you place the machine; it changes the schedule materially.

Beyond frequency, consistency has independent value. Same day each cycle means the location knows when to expect you, you can batch efficiently, and gaps become obvious instead of creeping up.

The professional version of this problem isn't "how many days" — it's par levels.

A par level is the quantity a slot should hold at the start of each cycle, set so it doesn't run out before your next visit. Work it out per slot:

> par = (vends per day × days between visits) × a safety buffer

A slot selling three units a day on a ten-day cycle needs 30, plus buffer — so 35 to 40. If the slot only holds 24, you have three options and should pick deliberately: service more often, give that product a second slot, or accept running out.

That last decision is the one operators make by accident instead of on purpose, which is how bestselling items end up as the emptiest slots. Your best seller should get the most capacity, not the same as everything else.

Once par levels are set, restocking stops being a judgement call. You count what's there, top up to par, and note anything that hit zero — because a slot at zero means your par is too low, not that you were unlucky.

With one machine, frequency is all that matters. From about three onward, the geography dominates.

• Cluster geographically. Machines within a tight radius should share a service day even if their ideal cycles differ slightly. Servicing a nearby machine a day early is nearly free; a dedicated trip across town is not.
• Set a route day. One or two fixed days beats scattered one-off trips. Fewer trips, less fuel, and less mental overhead.
• Load the vehicle to the route, not the machine. Take what all the machines on today's run need, plus a small buffer of your fastest movers for the surprises.
• Anchor to the strictest machine. In a cluster, the machine that runs dry fastest sets the cycle for the group.
• Keep a small emergency box in the vehicle. Water, the top-selling soda, the top-selling snack. It turns "I'll come back" into a two-minute fix.

This is also why placement proximity matters so much when you're starting out. A machine forty minutes away can be profitable on paper and a genuine burden in practice, because it can never share a trip with anything else.

A consistent routine is what keeps small problems from becoming location-losing ones. Roughly ten minutes:

1. Note what's low or empty before you touch anything. This is your par-level data. Skip it and you're guessing forever. 2. Check dates and pull anything close. One expired item costs more in trust than the unit costs in money. 3. Restock to par, rotating older stock to the front. 4. Test the payment path. Card reader and bill validator, an actual vend. Faults discovered by customers get reported as "the machine's broken" — or not reported at all. 5. Clean the front and the glass. Two minutes. It's most of how the location judges you. 6. Empty cash, if applicable. 7. Say hello to whoever's there. Thirty seconds of relationship is the cheapest retention you'll ever buy, and it's how you hear about problems before they become complaints.

Record it. Which slots hit zero, which are barely moving, what you replaced. That log is what tunes par levels, feeds the cut list from the product-mix guide, and builds the shopping list for next time — and it's precisely what the fleet manager automates once tracking it on paper stops scaling.