Extremely short edges might cause problems with splitting and such.
What is it that you are trying to do with these meshes? Are you running into problems somewhere?
-wim
Hi Hayden - I suppose that it depends. A mesh face with an extremely short edge will not add any valuable information to the scene - you won’t see it and wouldn’t miss it in a rendering. If a large portion of your file consists of such faces, it will lead to an unnecessary big file that will probably take a longer time to render (though, I suppose that a render engine might have a smart way of dealing with such). I would think that the portion of all faces in your scene needs to be really high for this to become noticeable, though.
If you think that you are facing unexpected file sizes or render time, we’ll need to have one of the render guys chime in here.
-wim