Ed posted something in another thread that I feel is most applicable to your question about magical hygiene.
As Ed stated, the first rule of magic is: yes, this is all in your mind.
If you do not "put down that which you call up" you are creating psychological archtypes that you may not wish to have idly interacting with your subconscious mind as your sitting at work or otherwise going about your day. A banishing puts such subtle influences to rest.
It bears mentioning that the choice to do so is a function of the work being performed, but I believe that Jim was just attempting to call awareness to the fact that it is not to be overlooked.
If you want to walk around with such things influencing your actions, more power to you, just be aware of what it is you are (or are not) doing.