In December 1846, Lieutenant Harry Lumsden raised the Corps of Guides in India, and the dust-colored dress that unit wore is where khaki as a military color begins. The word itself is Urdu for dust-colored, and it traveled into English by way of the British Indian Army. A couple of years later, William Hodson spoke of making the Guides invisible in a land of dust. I like that the most wearable neutral around started as a plan to disappear.

That is the thing about khaki pants: they were built to blend, so the work is in the cut. A pale, slightly worn-in color forgives almost everything, which is why October is its best month. Pair them with a navy knit, a brown leather belt and loafers, and you are dressed for the first cold morning without trying.

Start with the straight leg, because every other shape is a variation on it. The Still Here Painter Slacks sit low on the waist in a clean, worn-in cotton, and I would wear them with a boxy white tee. The Still Here Host Pants in stone are the opposite mood: a technical weave with a drawstring waist and drawstring hems, good for travel days. For something sharper, the BODE Standard Trouser is 100% cotton and made in USA, and the SEV Tailored Straight Pant is smooth virgin wool with slant pockets, which makes it my pick for a desk. The Nili Lotan Lorimer in washed French khaki is the five-pocket one I would keep for weekends.

Before you buy any of these, sit down in them in the fitting room. A straight leg should keep its line when you are seated, with no pulling at the knee and no gap at the back of the waist.

Wide-leg khaki is where the old uniform color gets its drama. Fabric does the work here: the same dusty shade reads casual in cotton and almost evening in silk, so check the material before you check the size.

The Nonchalant Label Alexis Trouser in camel has front pleats and a high waist, and I would run it with a fitted ribbed sweater. The Favorite Daughter London Trouser is cropped wide at the ankle and comes with a belt, so it likes a low heel or a clean sneaker. The AEXAE linen trousers have a front crease and a long relaxed leg, and the Polo Ralph Lauren Beaton is a cotton-linen blend with a flowing line. The Jenni Kayne Newport adds a button tab waist, and the TOM FORD pleated pant is silk with a belted waist, the one that makes khaki feel dressed. The R13 Janine is the surprise: light khaki corduroy with a deep leg, which is a very October fabric.

Test a wide leg by walking toward a mirror, then turning. The hem should clear the floor or sit just on your shoe, and the pleats should lie flat instead of fanning open at the hip.

What I would skip: the very long, floor-skimming cuts like the LESET Lauren if you plan to wear flats. They want a heel or a platform, and puddled hems get ugly fast in wet leaves.

Chinos are the same idea with a different story. Twill trousers gained popularity in the United States when Spanish-American War veterans came home from the Philippines in their military pants, and nobody can say for sure why they ended up calling them chinos. The cloth is a plain, tough cotton twill, and that plainness is the point.

The Alex Mill 9th Street Pants are 100% cotton twill in light khaki, with an optional self-belt and patch back pockets. The ASKK NY Twill Pants are mid-weight cotton twill made in the USA with slant hip pockets, a pair I would hand to anyone who wants a chino that looks like a chino. The Lands' End high-rise Rail in desert tan has a crisp twill finish with a little stretch. For a looser mood, the GRLFRND Farren Curve is a khaki-yellow chino with a slouchy curved leg, and the Mavi Kathleen is pale stretch twill you can cuff. The Vince Avery is washed stretch cotton cut straight to the ankle, which shows off a loafer or a boot.

For the fitting room, sit, crouch and lift your arms. Twill should give a little at the seat without bagging out at the knee, and the rise should stay put when you bend.

What I would skip: very pale chinos with a thin pocket lining if you carry keys and a phone. They show every outline, and darker khaki hides it.

Cargo pants are the part of the khaki story that never left the barracks, only got quieter. The trick now is volume you can control: pockets that lie flat and a hem that finishes the leg.

The La Ligne Clark Cargo in camel twill has big thigh pockets and a barrel-straight leg, and I would wear it with a tucked-in tee and a trench. The Pistola Wren Utility Pants are 100% cotton in wheat with large front patch pockets and flap back pockets. The Splits59 Nico Airweight is the light one, taupe-khaki with a drawstring waist and a gathered hem, and the Helsa Chino Cargo is organic cotton in pale khaki with a straight leg. The Zimmermann Rebellion has buttoned adjusters at the waist and ankles, so you can change the shape through the day. The Citizens of Humanity Marcelle is a stone-khaki twill cargo with a curved barrel leg.

Test the pockets before anything else. Put your phone in each one and walk, then check that the pocket stays flat against the thigh and does not drag the fabric down.

What I would skip: stuffing every cargo pocket. These work as shape, not storage, and one full pocket will pull a whole leg off center.

Pleats and curves are how khaki stops looking like a uniform. A barrel leg bows out at the thigh and returns to the ankle, and a deep pleat gives the front some weight, so both look best with a plain, fitted top.

The Veronica Beard Sloan is bark-tan stretch-cotton twill with a curved barrel leg and army-fatigue pockets, a nice nod back to the military roots. The FIFTEEN TWENTY Sondra is crisp stretch poplin in stone with patch pockets and the same curved shape. For pleats, the Helsa Tomboy Pants in heavy poplin have deep front pleats and a belt, and the Faherty Seafarer is a high-waisted pleated chino. The Lee Pleated Slouchy twill is the loose, balloon-like one in city limits khaki. The Nili Lotan Alphonse in Roosevelt khaki is virgin wool tailoring, made in USA of imported materials, for a day when you want a suit feel without a jacket. The Favorite Daughter Pleats For Days is camel with big sculptural pleats.

Check the pleats by standing straight and looking down. They should stay closed at the waist, and on a barrel leg the curve should hit at the widest part of your thigh.

What I would skip: a barrel leg with a long chunky boot. The proportion gets heavy, and a slim loafer keeps the curve readable.

Pick the leg first, then the fabric. If you wear one pair for everything, a straight twill chino is the safe answer. If you want a pair for dinner, go for a pleated wide leg in wool or silk.

Check the fit while sitting, then walk to the mirror and look at the hem. Khaki forgives a lot of things, but never a bad rise.

Lumsden wanted his men to vanish into the landscape. I would rather have the pants stand out a little, in the right way: a good hem, a good pleat, a fabric that feels like the season. Then I would put on a navy sweater and go outside before the light changes.