They can last as little as 2-3 years with very regualr use but often last much longer. If your bike is feeling a little 'loose' or clunky this is probably the main culprit. If the play/ movement in the hinge is more than 2mm in any direction it should be replaced.
One of the easiest overlooked sources of damage to the Brompton frame is overtightenting of the seatpost clamp due to a worn sleeve. This is a 'sacrificial' part designed to wear as the seat post is repeatedly adjusted on these bikes. Replace every 2-4 years on a very regularly used bike.
Main Frame Hinge Spindle Replacement
The main frame hinge will eventually develop play on older bikes, and those with heavy use.
This includes the rear pivot replacement. A relatively common upgrade with people replacing an old corroded triangle or upgrading to the standard bike hub or titanium version.
We can aslo fit racks and mudguards, carry out gear upgrades, change gear ratios, upgrade hubs, build wheels and upgrade suspension.