If I tell you that a week ago, I opened a packet of Dextro Energy tablets (orange and Vitamin C) with a best before or use by date (not made clear) of 10/2016 ......
I'm chomping my way through them. Chomp being the operative word as they are rock solid.
Largely we tend to turn a blind eye to best before dates, but if we have, (example), a bottle of olive oil, nearly finished, which is now a year out of date, Mrs O has no compunction about ditching it.