My MIL has a drinks cabinet with a pretty heavy drop front - one of the ones with a glass mirror inside. The original stays were made of brass, but after they broke about 10 years ago, I've only been able to get replacement sliding stays with nylon runners. The weight of the door means that unless you are very careful when you open it, the nylon part breaks off the sliding stay. So far we're on our 3rd pair in 5 years and they need replacing again.
Does anyone know of any widely available version that is going to last a bit longer than these