I wore a suit to the office today, for the first time in probably 5 years. It was a pants suit – a suit suited to Hillary Clinton, you might say.

Since my work team settled into our new high-tech, low-walled digs earlier this month (we’re all still speaking to one another, by the way), we have withstood regular “tours” of colleagues keen to check out our fancy space. This morning we were scheduled to welcome the granddaddy of all tours, by the biggest of our company’s big wigs. And so, we were expected to dress up.

Years ago I pledged myself fully to business casual, and so have only two suits tucked away in my closet. Trying them on last Friday evening was a nail biter. If they no longer fit, I would be spending my weekend shopping, instead of Olympics-watching while the soothing rain beat against my windows. Luckily, everything buttoned, snapped or zipped as intended, and my cocooning weekend was saved.

On this morning’s commute to the office, I had flashbacks of living in Manhattan after college, and riding the E train to work. We were packed in like veal, and condensation ran down the bus windows while perspiration ran down me. As I suffered, I remembered how happy I was to say goodbye to pumps and pantyhose, and layer-upon-layer of dry clean only. Denim breathes, am I right?

In New York, you’d have to look closely to spot the difference between Friday attire, and what we wore on every other workday. Business casual at a bank only meant your blazer and skirt could be made of different fabrics. Jeans at an office? Not unless you were paid to clean it.

Later, when I moved to San Francisco and joined a large brokerage firm, business casual had morphed a little – but some in senior management fought the trend. Even after it was officially sanctioned corporate-wide, the head of my division prohibited shirts without collars for men. I don’t care if you were wearing a silk Armani t-shirt under a cashmere sweater… if he spied you, he sent your boss a curt email threatening to send you home next time.

Twenty years later, nearly everyone I know is casual, every day. So it’s strange, when you think about it, that interacting with the C-suite still means full business attire. As one of my teammates pointed out, we ride the elevators and share the lobby with these executives; surely they’ve seen what we usually wear?

(Besides, I’m not sure I stood up from behind my desk during the tour; I could have been wearing culottes and high-tops under there, for all they knew.)

I suppose one explanation is, formal business attire is a known quantity. Instruct a team to wear it, and everyone will understand: men in ties and jackets, women in dresses or suits.  But business casual can run the gamut from polished… to looking like something best worn to clean out the garage.  Remember interns in flip-flops at the White House?

Business casual is here to stay – it’s too late to un-ring the bell.  And I’m very happy about that. It saves me a bundle on dry cleaning. But at least in my industry, putting on the dog for senior management isn’t going away either — and that’s OK. We have one more tour this week, and I’ve got one suit left before I have to repeat today’s ensemble.

Come Wednesday, I’ll be getting my denim on.