“There’s just a different standard in New England that’s been set by two-decades of generational play.”
Your attention, please: There’s a global shortage of hyphens, so we do not want to use them unnecessarily.
Especially when writing about time periods, follow these simple guidelines:
The adjective form is hyphenated: A two-decade tradition.
The noun form is not hyphenated: Two decades of play.
Think of the brain — I mean the brain of someone who speaks and reads English — limping along, from word to word, urgently needing to be spoon-fed. (Well, that’s a bad metaphor, but whatever.) When you come upon a “time-period word” like two, you expect the next word to be the noun you’re talking about: decades. And in this sentence, you get what you need: set by two decades of generational play.
But let’s say you’re talking about a two-decade tradition. When you get to the word two, the next word isn’t the noun you’re talking about. The next word is decade, but the noun you’re talking about is tradition. The words two and decade are working together, to describe the noun tradition. To make this easy for the narrow-bandwidth brain of the English-speaking reader, you have to glue the descriptor words together: a two-decade tradition. This is a valid use of our ever-diminishing supply of hyphens.
Thus: A two-year-old is two years old.
NOT: A two year old is two-years-old.
(You may have a better way of explaining this rule of English usage, and if so, I hope you will enlighten us all, via the Comment window. Until then, I’m going off to nurse my headache.)