development, I update my resume at the end of each month!
As I already stated before measurement improves results so by that  
acoount, my each months resumes updates shows me how I am improving  
and what new skills and projects I have added to my professinal life.
This April I completed my 4th resume update of this year and am quite  
happy with the progress I have made so far. Apart from picking up some  
new stress tool, i have build upon my vba knowledge base. Each month I  
don't necessarily add a new tool set but improve upon an existing one.
I think this an easy and objective way to access yourself when you are  
working.
Usually I update my resume and upload the same to a job site. This  
allows the job site to sent me the relevant job opportunities that are  
available in my area of work. This weekly job reports also points me  
to the additional skill sets the companies are looking for a person of  
my profile.
So if you are working and want to improve yourself professionally  
begin updating your resumes every month. It really helps!