"Fashion is for women; style is for men."
I've seen that quip attributed to various people. Regardless of who first said it, it's true.
Classic men's clothes never go out of style; they may go out of fashion among the trend-following masses, but you shouldn't be overly worried about fashion anyway.
Style is basically timeless (at least within a given person's lifetime). Classic style follows the natural lines of the body and rules of proportionality, and utilizes natural (or natural-looking) fabrics and colors and shades that are pleasing to the eye.
Fashion, on the other hand, is transitory because it runs counter to these principles. It's merely an attempt by the clothing industry to sell more clothes. As G. Bruce Boyer has noted, following fashion is the most expensive way to dress, because it requires you to throw out (or put into storage) clothing that's still in good physical condition just because some designer arbitrarily decrees that such items are "out," and that something new is "in."
Think about it: things like over-padded shoulders or flared (bell-bottom) trousers run counter to the natural lines of the body. The skimpy lapels of the 1960s were out of proportion to the rest of the garment and to the proportions of the body, as were the lapels of the 1970s that were two-thirds of the way to the shoulders. Ditto the one-inch ties of the 1960s -- and the five-inch ties of the 1970s.
Things like natural-shoulder, 3/2 roll jackets; trousers with rises appropriate for wearing on the natural waist and with moderately-tapered legs, hemmed long enough to cover the socks when walking, but short enough not to puddle around the ankles; natural (or natural-looking) fabric shirts with collars of a moderate length; and natural fabric ties 3-4" wide are classics that stand the test of time. (This list isn't meant to be exhaustive; it's just a gallop through some classics.) Such things have remained basically unchanged amidst a sea of fads for more than 100 years, and they're likely to last at least another 100.
Whenever I hear someone say something like, "That went out of style two years ago," I know I'm dealing with someone who's clueless about real style, but who thinks he's a sharp dresser because he's in step with all of the trends.
"Those long collar points looked great in 2008, but now, not so much." WRONG. If something doesn't look good now, then it never looked good; it just seemed less ridiculous at the time because all of the other clueless, unstylish lemmings were wearing it too.