Hi there and thank you for your replies.
There are several reasons why quads are preferable to triangles. First of all, as correctly mentioned above by barkest, for UV mapping. However, another important reason is when using subdivision surfaces to smooth out geometry. Subdivision surfaces doesn't like triangles.
The funny thing is that some objects are quads, some are mixed quads and triangles and others are simply triangles.
Is there any way to "force" quads for everything.
Untriangulating after the fact doesn't work all of the time.