I am currently working for a client who are petrified of changing lousy un-testable and un-maintainable code because of \"performance reasons\". It is clear t
Variable re-use.
I used to do this all the time figuring I was saving a few cycles on the declaration and lowering memory footprint. These savings were of minuscule value compared with how unruly it made the code to debug, especially if I ended up moving a code block around and the assumptions about starting values changed.