Notice: the thing every store case turns on

When the store's own conduct created the hazard, you generally don't have to separately prove they knew about it. They made it — knowledge is imputed. This is why falling merchandise and freshly-mopped-floor cases tend to be stronger than random spill cases.

This route lives in records: internal communications, prior incident reports, complaint logs, and — most often — the testimony of the employee who was standing right there. It's also why the offhand remark an employee makes right after a fall matters so much. 'I told them about that leak last week' is actual notice, spoken out loud, and it will not be repeated once a claims department gets involved.

The hardest and most common. The hazard was there long enough that a store exercising reasonable care would have found it. There is no fixed number of minutes; it's a reasonableness question weighed against the store's own inspection practices.

Which is why the store's sweep logs are so useful — they establish the standard the store set for itself. If the policy is a documented inspection every 30 minutes and the fall happened 50 minutes after the last one, the store has defined its own failure.

Physical evidence also speaks to duration. Liquid with dried edges, footprints or cart tracks through a spill, dirt mixed into it, melted ice, a wilted or blackened piece of produce — all of it is evidence the hazard had been there a while, which is why photographing the substance itself matters more than photographing the aisle.

It has real limits. A hazard can be visible in the abstract and still unreasonable — a store that fills its aisles with merchandise specifically designed to pull your eyes off the floor is not on strong ground arguing you should have been watching the floor. Many states have also moved toward treating obviousness as a comparative fault factor rather than a complete bar.