This is what an interchangeable wardrobe gets you: a whole lot of bang for your buck.
We're presenting a very simplified example here, just considering jacket and trouser combinations.
Keep in mind that each combination can be worn with multiple kinds of shirts, neckties, pocket squares, shoes, and belts, as well as with extra layers like sweaters and vests.
So even keeping it simple we're going to turn five pairs of trousers and five sport jackets into twenty-five outfits — and that's the bare mathematical minimum.
With a few good shirts and accent pieces you're talking more like fifty to a hundred outfits.
If you don't have these basic fabrics in the wardrobe yet, it's time to think about them:
Trouser Fabrics
These are all basic styles of trousers that you can find at any good menswear store. You don't have to buy them in particularly unusual colors or cuts — just these interchangeable pieces will be the backbone of a hugely varied wardrobe.
If you don't have one yet, consider owning at least one pair of the following:
Gray Flannel Trousers
· Typically worsted flannel (smoother), not woolen (fuzzier)
· Medium-gray — not as dark as a charcoal suit's trousers
· Traditional staple of menswear
· Acceptable business-casual paired with just about any jacket
Cotton Drill Khakis
· Compact, diagonal weave looks solid at a distance
· Originated with military uniforms — sturdy, low- maintenance
· White-collar (non-suit-wearing) office staple
Dark, Fitted Blue Jeans
· Easiest way to “dress down” a jacketCan pair with more casual shoes (canvas sneakers, etc.) than other trousers
· Looks more natural with a non-collared shirt under   the jacket than other trousersBrown Gabardine
· Can be a wool or a cotton gabardine — former good in winter; latter in summer
· More multi-colored effect than drill — woven of mixed lighter and darker threads
· Solid earth-tone base for either a darker or a lighter-colored jacket
Colored Corduroys
· Relaxed look that's a bit more stylish than blue jeans
· Can be a basic menswear color (navy, brown, black) or more adventurous (red)
· Softer look works well in looser fits than other materials
Jacket Fabrics
Gray Herringbone Tweed
· Goes-anywhere jacket — always acceptable, as long as you're not in the suit-and-tie territory
· Sturdy and warm
· Textured weave and varied color adds visual interest
Brown Corduroy
· Casual sporting jacket for weekend and outdoor wear
· Good match for anything blue
· Softer fit makes it very relaxed-looking and comfortable
Worsted Tartan
· Colorful option for when you want to stand out a bit
· Can range from mostly-gray Prince of Wales to deep blue-and-green patterns
· Worsted rather than woolen threads gives a smoother surface
Pinstripe Woolen Flannel
· Charcoal gray with light pinstripes — similar to suit jacket, but cut softer
· Has a slight fuzziness from the woolen threads that makes it casual and soft-looking
· Slightly dressier look — good for evenings at nicer places
Camelhair
· Paler color makes a nice contrast for darker trousers
· Good soft, uniform texture — easy on the eyes and easy to match
· Very classic daytime casual wear
