Same company, different CEOs for 30 years. We could wear Levis and shirts with collars maybe until early 1980s. Then Levis were banned, ties were required for staff, so I had three ties at work (one black-ish, one blue-ish, one brown-ish), and daily chose the tie that I felt matched best. Mid 1990s new CEO ditched ties, but a few still wore them, the feeling here is that those were a feeble attempt to try to make up for their lack of technical expertise. So now I wear $15-$20 cotton pants from Target and a "golf" type shirt everyday. I only wear a lab coat in the one lab that's real cold. They buy us shoes with steel toes, but there's no way I need those in my job, but I don't need to buy shoes for work.
No Levis except on designated special days, or for cleanup work anymore.
One time, the R&D Director put out a dress code memo, and it detailed that if there were any questions that one should "feel free to talk to him". That memo stated "no jeans", so I asked him if jeans meant the the type of fabric (denim) or the cut of the pocket/pattern; he replied "isn't that obvious?", and I told him if it was obvious that I wouldn't have asked.
Anyway he could not answer my question, he just got pi$$ed.