Midi dresses have become the default length, and that is good news for anyone who wants a dress that can move between an ordinary day and a proper occasion. The hem usually lands in the useful middle ground: longer than a mini, less ceremonial than a gown, and easy to work with under a coat. I judge a midi by what happens after the first impression. Can I sit down in it, wear it with a flat shoe, and put a jumper or jacket over it without losing the shape. If the answer is no, it is an event dress pretending to be practical. My other rule is to choose the fabric and construction before the print. A simple satin dress with a good waist will earn more wears than a complicated pattern that only works with one pair of earrings. Price is personal here. The Altuzarra mitchell jersey midi dress at $995 is a serious purchase, but a well-made jersey shape can be more useful than a cheaper dress that needs constant adjusting. At the other end, the Agua By Agua Bendita alcaparra brisa floral print embelished cotton midi dress at $950 still needs to justify itself through more than one occasion. I want a midi to be the thing I reach for when I have no time to think. Below, the versions that make a convincing case.

Zimmermann does occasion dressing with a lighter hand than most labels, and its midis are strongest when the detail is allowed to carry the silhouette. The aster ruffled denim midi dress at $995 is the one I would wear most often, because denim gives the romance some discipline. The valiant deco striped ribbed jersey midi dress at $1,100 is a better day-to-evening option than its price might suggest, while the belted denim midi shirt dress at $1,075 has the useful authority of a shirt without becoming office uniform. For a more formal mood, the valiant belted striped satin midi dress at $1,250 and the valiant satin trimmed lace midi dress at $1,850 make the case for keeping one beautiful dress in the wardrobe rather than five almost-right ones.

Silk and satin midis are for evenings, weddings and the days when getting dressed should feel slightly theatrical. The Emilia Wickstead joelle floral print silk midi dress at $2,040 has enough print to carry the room, while the Victoria Beckham bela gathered satin midi dress at $1,390 is quieter and more adaptable. The Alessandra Rich belted polka dot silk crepe midi dress at $2,160 is the dressier choice, and the Alessandra Rich ruffled silk crepe de chine midi dress at $1,815 brings its own movement. I would be suspicious of any satin midi that only works with a heel. Test it with a flat shoe before deciding it is worth the money.

Knitted and jersey midis are the workhorses, provided the knit is doing something more interesting than clinging everywhere at once. The Altuzarra mitchell jersey midi dress at $995 is a clean starting point, while the Proenza Schouler monet ribbed knit cotton blend midi dress at $1,490 has enough texture to hold its shape. For colder months, the Khaite seberg merino wool knitted midi dress at $2,900 is the kind of dress that can replace several layers. The Missoni striped metallic crochet knit midi dress at $2,790 is less discreet, but it makes sense when the dress is meant to be the whole outfit. Keep the accessories plain and let the fabric make the argument.

Printed and textured midis are best when the surface detail has a clear relationship to the cut. The Oscar de la Renta floral print cotton poplin midi dress at $2,990 has the easy structure I want from cotton, while the Carolina Herrera striped ruched cotton blend midi dress at $1,990 makes a stronger case for a close-fitting shape. The Fforme lumie lace trimmed pleated satin midi dress at $1,695 is for someone who wants texture without a loud print. If you prefer a sharper statement, the ERDEM asymmetric cotton blend tweed midi dress at $2,595 has enough construction to stand on its own. Prints are not a substitute for fit, so check the waist and shoulder before admiring the pattern.

The Shopping List gathers the midis that refuse to behave like one category. The Alaïa knotted woven midi dress at $4,050 is a full commitment, but the construction gives it a reason to be. The Altuzarra lollie ribbed and woven midi dress at $1,495 is easier to imagine wearing repeatedly, while the Victoria Beckham gathered jersey midi dress at $1,270 is the one I would pack for a trip. For a more formal wardrobe, the Dolce & Gabbana paneled satin bustier midi dress at $3,495 and the Oscar de la Renta embellished tweed midi dress at $4,890 are both very much the occasion. The Emporio Sirenuse johanna ikat striped cotton midi dress at $1,490 is the escape route when you want pattern without ceremony.

A midi dress should not require a special life. I would rather own one that works with sandals, boots and a jacket than one that only makes sense under flattering evening light. Check the hem while standing and sitting, because the length changes the balance of the whole dress. Satin benefits from a proper hanger, and knitted dresses should be folded rather than left to stretch on a rail. If the waist is right, most of the rest can be adjusted with shoes and a sleeve pushed up. Phoebe