I found it to be very helpful to use a macro-specific “namespace” for variables, especially for bigger macros. For example essPath or ESS__Path, where the prefix hints at the macro name.
This makes it easy to clean up the variables when you no longer use the macro — and also for other users who just download and try the macro.
[Edit: Added screenshot:]
The inverse effect of this is that you also can easily spot unprefixed, “messy” variables, introduced with one-time test runs of third-party macros.