Classes Vs COM

For the majority of my work, I just use plain ASP. On the rare occasion that
I am doing something intensive that does require user interaction I might
create a COM component (ie where performance gain outweighs the overhead of
COM).

A simple Rule-of-Thumb. I imagine this is fairly common practice... (I hope
it is, at least).

However, I'm curious about VBScript Classes. I would have imagined that if a
page was complex enough to merit defining and creating your own
classes/objects, that COM would be appropriate...

In which case, when and how do people use VBScript Classes?