Questions such as Are Non-Stick Bread Pans Destined to Fail? conclude that non-stick pans do not last forever, especially cheaper ones. I am trying to find some information that allows me to quantify this to some extent.
I normally use teflon non-stick pans some 3 times a week. I only use wooden and plastic tools on them, never metal ones. For some dishes, however, it is necessary to exert some rather punctual pressure (through the food) on the pan's surface, as well as dishes that require quite some oil (sometimes added in between, i.e. while the pan is heated) even in non-stick pans in order to not stick.
In my experience, my teflon pans live for some 3 to 4 years before they start showing some minor, but visible blank spots of one or a few mm² where the teflon has disappeared. Which is when I start considering looking for a new pan.
At my usage rate, is this within the expected lifetime range of teflon pans? or, asked more generally, What is the approximate expected lifetime for teflon-coated non-stick pans?