Avoid saving your CV with an irrelevant file name.Some people like to save their CV with a file name like, CV of Jacob Mendez for Marketing.doc. This annoys the receiver and also tells them that you have crafted your CV for a position in marketing.
Modifying a CV is a good habit but giving the other party an impression that you might have played heavily with your CV is not good. This may cost you the opportunity. Small things in communication say a lot about you.
When you save your CV on your local machine, save it with a sensible name like CV_Jacobm.doc or CV_Jacob_Mendez.doc for example. This ensures that your CV is not lost in the database and is easily accessible.