Well... 727 - slightly older than me. Youngest airframe? Circa 1986? Alitalia as I recall picked up some the last off the line. 1000 or so aircraft. Plenty still flying and lots of useful spares.
1-11. 260 or so built between the mid-60s and about 1980, plus the RomBACs. How many still fly? Not many I'd guess, and dwindling spares.
BAe 146 - 20 or so years in service - but a much lower airframe count than the 727. It'll go for a while yet in service, those parked up (as at Kemble last weekend) will find new revenue customers, or be scrapped for spares to provide for the rest. Sad, but inevitable. Plenty of 737s and A320 series aircraft about which attract the buyers.
Longevity has been the 727/737 watchword. The 146, sadly, will not enjoy such elongated popularity I suspect. But Airbus, and by association BAe, may yet have the last laugh. Watch this space for some decades to come...!