How to Automate Supplier Purchase Scheduling

At most Mexican businesses, buying from a supplier works like this: someone notices something is almost out, tells the owner, and the owner orders. Sometimes they order too much because there was a promotion, sometimes too little because cash flow was tight, and sometimes they only find out something was missing when a customer asked for it and it wasn't there. There is no system; there is memory and a good eye.

That method works while the business is small and one person sees everything. It stops working as soon as there is more than one point of sale, more than fifty SKUs, or more than two people who can sell. From there on, both ways of losing money coexist: what sells best runs out, and what barely moves piles up. Both hurt, but only one is visible, which is almost always why the wrong one gets fixed.

What actually goes wrong when you buy?

What goes wrong is that the purchase decision gets made with today's number instead of the month's number. When someone looks at the shelf and decides, they see how much is left but not how much sells per week or how long the supplier takes to restock. Without those two numbers, every purchase is a bet. And that bet gets made every day, across dozens of products.

It also fails because no one distinguishes between products. A business with two hundred SKUs can't treat them all the same: twenty of them drive most of the sales and should never run out; another hundred barely move, and over-ordering them just freezes money in the warehouse. When you buy evenly across the board, you end up with excess of what doesn't matter and shortages of what does.

And the supplier's lead time fails too, because it's almost never written down. If your supplier takes ten days and you only notice the shortage once you've run out completely, you'll go ten days without selling that product no matter how fast you talk. The reorder point isn't when it runs out: it's when there's enough left to get you through the time it takes to arrive.

What part of this process can be automated?

• Calculate each product's average weekly sales using the data you already have in your point of sale.
• Track how long each supplier actually takes to restock, not what they promise.
• Set a reorder point per product that combines that average sales rate with the real lead time.
• Automatically alert you when a product hits its reorder point, before it runs out.
• Group shortages by supplier and put together a suggested purchase order ready for review.
• Flag the opposite too: products with no movement in ninety days, which is money sitting idle.
• Keep the history so you can see last year's season and plan ahead for this one.

What doesn't get automated is the final call. The suggested order is just that, a suggestion: the owner still decides whether to take advantage of a promotion, bet on a season, or tighten purchasing because cash flow is short. The difference is that now the decision is made looking at numbers instead of intuition, on a list someone else already put together.

The reorder point isn't when the product runs out. It's when there's just enough left to get you through your supplier's lead time.

What is it worth to put this in order?

It pays off on two sides. On the sales side, every shortage of a product that actually sells is a lost sale and sometimes a lost customer, because whoever went looking for something and didn't find it goes straight to the competition next time. On the money side, slow-moving inventory is sleeping capital: merchandise that was bought and hasn't turned into cash, that also takes up space and sometimes expires.

There's a third, less obvious benefit: the owner's time. Putting together the month's purchase order by checking shelves and calling every supplier eats up whole days that almost always come out of the weekend. When the system arrives with the list already organized by supplier, that work shrinks to a half-hour review. Custom Software built for the business does exactly this, connected to the sales data that's already being captured every day.

Where to start without overcomplicating it?

Don't start with all two hundred SKUs. Start with the twenty that sell the most, which are almost always the ones that generate the most revenue and should never run out. For each one, write down three things: how much sells per week, how long the supplier takes to restock, and how much you want to always have on hand. With those three numbers you can already calculate the reorder point and set up an alert, even if it's manual at first.

Run that setup for a month and measure two numbers: how many shortages you had in those twenty products, and how much the time you spend putting together the purchase order dropped. If both improve, you already have the case for extending it to the rest of the catalog. It's the least risky way to get purchasing in order: start where it hurts most, then move to everything else.