Handknits should, in my opinion, keep going for years, decades, sometimes generations. But it takes effort. It's a bit like conservation of a piece of art. Knits must be cleaned of sweat, food, dust, grime, the buttertart that leaked down its front last week, etc. Holes need to be repaired, pills removed, stains treated. That's what I'm doing during our September warm spell. The warm weather with low humidity makes for quick drying. My Modern Gansey is currently drying on the dining room floor after a day of multiple treatments for its buttertart accident. Sunlight dish detergent as well as Eucalan were involved. Not to worry; all is now well (whew!) It'll be part of KnitEast's fashion show in less than two weeks.
The collection of knits already refurbished for fall is growing.
The Bibliogloves, like the Modern Gansey, are in Quince's "Glacier" (but in Chickadee instead of Osprey). It's a truly beautiful colour, but let me tell you, boy, is it hard to keep clean. Worth it though.
Many designers keep a collection of never worn, pristine knits just for display at events like retreats and yarn fairs. I disagree with this approach. I want knitters to see how well-worn, well-loved knits look after years of wear and care. Maybe you've seen Elizabeth Zimmermann's famous aran cardigan with its shortened arms (due to worn out cuffs) and inventive heart elbow patches. That's how the life of a sweater ought to be lived!