[joshstaiger]

It's useful (at least for me) even if you only go to one store.

We use historical data to judge how good the sales are for items at any given time — and it’s surprising how much variation there is week to week.

Usually when I shop, I’m looking to get fresh meat and produce of some sort. If salmon is steeply discounted this week, I’ll spring for that vs chicken breast that is only slightly discounted from the norm.