One data point to add to the world: in a dishwasher that’s used every day, about three years, maybe more.
Back in 2020, I fixed the bottom rack of our dishwasher by printing some pegs and new wheels out of recycled PETG from a filament company that shall remain nameless.
The other day one of those pegs cracked, and I was able to rescue all the bits before they ended up in the heating element:
There’s an obvious layer of scurf and hard-water and soap deposits, and it’s also pretty clear that the pin cracked along the layer lines — probably some combination of lousy layer-to-layer adhesion and stress concentration (if a crack is going to form in a 3D printed piece, what better place than where the surface already has a V-shaped divot).
I printed a new peg-and-wheel combo out of whatever is on the machine at the moment, and we’ll see how long it lasts. The current stuff seems a little more flexy, but it hasn’t been through a thousand or hot wash-and-dry cycles, so who knows.