I've sort of settled into a 21+21 cycle for beers. I have a Kolsch yeast that likes to sit a little longer in primary and goes closer to 4 weeks before bottling, but everything else is good and ready at 3 weeks. Depending on the beer, I start chilling and drinking at 3 weeks, leaving some to condition for a few more weeks as I replenish the beer fridge.
I'm not sure when most beers are "best" but they definitely change for the better with longer conditioning and longer chill time. For English Mild or other small beer, 14+14 and chilled overnight makes for quite drinkable beer, but I'd guess 4 weeks in the bottle and a week in the fridge is a sweet spot for most.
Then there are those beers that just don't seem to be right and just get ignored for a while. I've got an IPA that had a pretty bold hop balance and was maybe slightly soured on top of that. It was never undrinkable, but just not really enjoyable. After 3 months in the bottle, it seems to have improved so much that it's actually an interesting beer now. I'll leave some in the fridge for as long as I can to see if it really gets good.