When Lands’ End, Middle America’s favorite mail-order haberdasher, introduced a custom-fit-chinos service last year, the company expected its appeal to be narrow: heavy people, very short people, the fussy few who demanded perfectly fitted casual clothing. But the service has caught on beyond Lands’ End’s greatest expectations, and this year the company extended its custom-sizing service from men’s and women’s pants to men’s dress shirts. In so doing, the retailer has begun to rewrite the rules of American casual dress.

The Lands’ End process is managed online. Instead of a well-mannered tailor discreetly judging the side to which a gentleman ”dresses,” an online form asks for measurements and follows up with blunt queries like ”The shape of my seat is best described as. . . . ” (The choices are flat, average, prominent/high and full/wide.)