While more than half of over-50s have a collection of some sort, two-thirds could be underestimating its value.
This means they could potentially be underinsuring their possessions, according to Saga.
Music (24 per cent), books (23 per cent) and pictures or prints (11 per cent) were the most common items hoarded.
However, the lion’s share (83 per cent) of over-50s failed to correctly value a Beatles publicity card, while even more (85 per cent) couldn’t guess the cost of a Patek Philippe watch. Silver fared better however, with one in four able to correctly estimate its worth.
One in five wine collectors failed to identify the price of a 1967 Chateau d’Yquem, valued between £1,000 and £2,000.
Londoners appear to be the keenest, with three-fifths saying they keep something. Those living in the north-east and Yorkshire and the Humber are the least likely with half admitting to being a hoarder.
Roger Ramsden, chief executive of Saga Services, said: “While few will have that undiscovered masterpiece, it is wise to have your collections valued regularly so that if the worst happens, then your insurance can help cover the cost of replacing your treasures.”