Just How Often Do Clothes Make the Man

I have to admit that I am not a slave to fashion. I am not worried about trends in clothing. (Or in just about anything else, for that matter.) I tend to purchase clothing, make use of it until it is not longer serviceable, and then discard it to buy new clothing. Given the rather decent quality of clothing I tend to buy sometimes, I have been known to keep certain shirts and pants for many years.
 
As I have been reading more articles about success on the job hunt and in the professional world, (particularly those written by the ubiquitous Gen-Y) I have learned that not only is this not the practice of most people, but that in some cases, some people insist that it keeps one back.

I can understand the need to look good when one is networking, or on the job. (Though I have never worked anywhere that required a suit.) Being smartly dressed on a date make sense. I even understand the psychological benefits some would garner by being smartly dressed even in private time. (Though I sometimes fall quite short on this one, I must say.) Yet some of the monthly (as in once every month) clothign budgets that some people recommend, I almost blanch. They run into the several hundreds of dollars, even for modestly employed people.

One even suggested that a monthly clothing budget should always be "two-thirds of whatever the food budget" would be.

I confess that my attitude towards clothing may be a bit on the conservative side. I shop for clothing perhaps once a year, or less. Not everyone will be as austere with their ensemble. But is replacing one's entire wardrobe several times a year really necessary to project success and competence? Do simply golf shirts and collared button-downs really go out of style so quickly in our society that if I am still wearing one I got in 2006 I am projecting a lack of pride in myself?

My clothes are always cleans, free of wrinkles, and lacking holes when I am out doing something other than exercising. Is this not enough?

Not that I am likely to suddenly change my whole clothing budget in the future, (I don't have the money for that.) But I am curious just how often any of you may replace entire wardrobes, and how crucial an expert knowledge of that years fashions is for your self improvement.