This is true, but unfortunately most breweries still dont give a bottled/canned on date, so it can be difficult to figure this out (unless there's some secret I'm unaware of). There's at least a couple beers I buy regularly that are great within a month or so, but will be pretty nasty after being on the shelves after a few months.

The only reasonably reliable way I've found to get around this is to buy refrigerated whenever possible, and to look for "what wasnt here last week". Or buy from one of the handful of breweries that does print dates.