Per Merriam-Webster dictionary:
[h=2]Definition of heirloom[/h]
: a piece of property (such as a deed or charter) that descends to the heir as an inseparable part of an inheritance of real property
2: something of special value handed down from one generation to another - The pin she's wearing is a family heirloom.
From this definition, I derive (parenthetically) that an heirloom--any type of heirloom :
-is a piece of real property (as opposed to an intangible thing)
-has been handed down from one generation to the next (at least once)
-has special value (which may be monetary, sentimental, historical, cultural, or a combination thereof)
I agree with ghostrider; no one can make a new heirloom quilt because, by definition, an heirloom has been handed down, not simply intended to be handed down. If I make a new quilt to be given to, say, my daughter as a wedding present, it's a wedding present, but it wouldn't be an heirloom because it hadn't been a part of my generation for longer than it took me to make it. (Of course, at the rate I go, that could, obstensibly, take 20 years, so.... LOL) Not until my daughter hands it down to her child, or niece, or whomever is a younger generation, would it be an heirloom.
I don't see that amount of use, quality of workmanship, or condition have anything to "heirloomnicity". (I like that word. :O )