Abram Sauer of Esquire uncovered a disturbing truth: you haven't actually maintained a 36" inch waist all these years. Men's fashions, like women's, reflect vanity sizing:
I enjoyed many of these pants, as I mentioned, but I'm still perturbed. This isn't the subjective business of mediums, larges and extra-larges — nor is it the murky business of women's sizes, what with its black-hole size zero. This is science, damnit. Numbers! Should inches be different than miles per hour? Do highway signs make us feel better by informing us that Chicago is but 45 miles away when it's really 72? Multiplication tables don't yield to make us feel better about badness at math; why should pants make us feel better about badness at health? Are we all so many emperors with no clothes?
Link via Ace of Spades HQ | Image: Esquire
You can of course have your own gauge such as "an inch short fits me perfectly" or "I like an inch of overlap for a comfy fit". You'd also be surprised by the variation in different pants of the same size and this quick check will save you several trips to the dressing room.
But then anybody who's waist measures 41" shouldn't be wearing trousers. A muumuu would be more suitable.
some pants appear to be intended to be worn at the hip level and on women, this would be significantly wider.
then there are the pants intended to be worn at the knees so that young men can show off their boxers...