For products a business buys, keeping them in stock means buying more when they run low. Reordering rules can trigger that buying automatically. This piece is about reordering rules that trigger purchase orders in Odoo.
Reordering rules for bought products
A reordering rule sets a minimum and maximum stock level for a product, and when stock falls to the minimum, Odoo generates the replenishment to bring it back up. For a product the business buys, that replenishment is a purchase. So a reordering rule on a bought product is, in effect, a rule that triggers purchasing: when the product runs low, the rule generates the purchasing needed to restock it. The business does not have to watch the stock level and decide to buy; the reordering rule does it.
How the trigger reaches purchasing
The reason a reordering rule on a bought product results in a purchase, rather than something else, is how the product is supplied. Odoo, knowing the product is bought, responds to the reordering rule's trigger by generating purchasing for it. So the reordering rule and the Purchase app work together: the rule detects that stock is low and triggers replenishment, and because the product is a bought one, that replenishment flows to purchasing. This is part of the connected operation, the planning, here the reordering rule, flowing a need into purchasing.
Why this is valuable
Reordering rules triggering purchasing are valuable because they keep bought products in stock without constant manual watching. For the many products a business buys and holds, a buyer would otherwise have to monitor stock levels and decide, product by product, when to reorder. Reordering rules automate that: the products are kept topped up against their defined levels, and the purchasing is triggered when it is genuinely needed. This means bought products are reliably available, without a buyer's continuous attention, and without the stock-outs that come from a low level being noticed too late.
Setting the levels with lead time in mind
Reordering rules that trigger purchasing depend especially on the minimum level being set with the vendor lead time in mind. When the rule triggers, a purchase is generated, but the goods do not arrive instantly, they arrive after the vendor's lead time. So the minimum has to be high enough that the stock lasts through that lead time after the rule triggers, or the product runs out before the purchased goods arrive despite the rule. Setting reordering rule minimums for bought products means accounting for how long the vendor takes to deliver. A minimum set without regard to lead time will produce stock-outs even though the rule is working.
Reordering rules and review
As with reordering rules generally, the levels for bought products should be reviewed periodically, since consumption rates and vendor lead times change. A minimum set against an old lead time, if the vendor now takes longer, will be too low. Keeping the levels current is part of using reordering rules well.
The takeaway
Reordering rules that trigger purchase orders in Odoo keep bought products in stock automatically: when a bought product falls to its minimum level, the reordering rule triggers replenishment, and because the product is bought, that replenishment is purchasing. This keeps bought products reliably available without constant manual watching. The minimum level must be set with the vendor lead time in mind, so stock lasts until the purchased goods arrive, and the levels should be reviewed as consumption and lead times change. For how we approach Odoo, see our ERP practice.