Is it necessary to reset or clear the global variables ?

[Fren Zeee]

Friends,

I am trying to modify or improve an existing lisp function written by
myself a few years ago. I have observed that when I run it on the test
data after some modification, it appears to run because the global
variables have old value and some regular expression or result did not
produce a nil or did produce a nil which resulted in the failure of
the function to die or crash during execution.

A standard method is to reset all global variables.

As a newbie, I ask you to provide me with advice on what is a good
practice.

Franz Xe

P.S. Is the word persistence an accurate term to describe this
disease ?