>I would side with Jim Nelson (I think) on this.
>
>If maintaining old code you should get you head round whats there and work with it. The example may not be lovely but it did look consistent.
>
>Also if it was working (mostly) and you rewrite are you not introducing many lines of new code(with possible errors) into a live environment.
>
Nick,

According to Steve McConnell in Code Complete, refactoring poorly written code is almost always beneficial over the long run.

My personal experience indicates that he's quite correct in this assesment. I often do this in order to help understand what the problem is. If you can't understand it, you can't solve it.