Buying trash liners seems like the kind of job nobody should need advice on. Then you buy the wrong ones, and by Wednesday the break room floor is sticky and somebody’s furious.

The main thing to figure out is what’s going into the bag. A restaurant kitchen throws out wet scraps, bones and glass. A warehouse throws out cardboard with sharp corners and bits of strapping. An office mostly throws out paper. Heavy bags in the office are money wasted, and thin ones in the kitchen are a disaster waiting to happen.

Size is the second thing, and people get it wrong constantly. Measure the can, then add enough extra on top to fold over the rim. A liner that’s too small falls inside the can. One that’s too big wastes plastic and drags on the floor.

Once you know what you need, compare real options. Browsing a range of polyethylene bags and liners in different thicknesses is a good start, but the best test is simple. Get samples, use them for a week in the actual can with the actual trash, and see what breaks. Spec sheets can’t tell you how your Friday night rush treats a bag.

If you use a lot of liners, buying direct from the maker usually brings the price down. A polyethylene extrusion packaging company makes its own film, so there’s one fewer middleman taking a cut, and they can often adjust size or thickness to fit what you use.

Color is worth a thought. Clear bags make it easy to check recycling at a glance. Black ones hide the mess. Some places use different colors for different departments so nobody has to guess where things go.

And watch how your staff actually handle full bags. Dragging a loaded liner across concrete will wear through almost anything. A cheap little cart can save more money than upgrading to a thicker bag.

Pick for the job, test it, then buy in bulk once you’re sure. That’s really all there is to it.