I've had my mezzo for a little over 3 years, and the hinge in the stem has developed a serious wobble
Over the years, tightening the hexes in the hinge got rid of this, but maybe six months ago this technique stopped working, so I decided to live with the wobble - it wasn't that bad then.
But in the last month I've done 3200km (hit 2000.1 miles on the 30th June) and the wobble has got pretty bad. I examined the joint and found the wobbling had been wearing out the metal. It's all smooth and shiny in there, and the two sides no longer nestle together.
It's not a safety issue, but I'm wasting energy wobbling rather than going forward, and I'm sick of the sneers I am getting from people that happen to handle the bike. I've bitten the bullet and taking it to the shop tomorrow to get a new hinge.
Still love it, though.