Sparked by a friend saying her dress was "pre-kids" - her oldest is 9!
I said I had nothing still going that was that old vintage.
Thinking about it I can offer a Laura Ashley belt which must be 10 yrs old, and a Racing Green scarf which I wear daily (in winter) - lovely red cashmere. It must be old as Racing Green no longer exists AFAIK - so let's say about 10 yrs too (I bought from there a lot before DS1 was born).
Otherwise my stuff always wears out/looks tatty/gets marks on it or ripped/doesn't fit or just looks out of date (hasten to add none of thse were true of my friend's dress!). I clear out anything I've not wron for 6mo.
What's your oldest garment still worn regularly?