Sorry, this is going to be long.
Insurance office, early 1990s.
Men - suit (usually pinstripe blue for the senior brokers and finance, dark grey or navy blue for the younger ones - light grey or double breasted was for 'wide boys and used car salesmen'), tie, white or mid blue shirt, brown polished Oxford shoes (brogues for the really out there individuals), dark socks. Leather brief or attaché case expected.
Women - straight skirt, long sleeved cotton blouse, nearly black or tan tights of a minimum of 15 denier (never black as that would be 'too racy'), blazer on at all times to avoid seeing a bra strap through the blouse, hair tied back into a smooth bun or a chin-jaw length bob if you weren't aged 30, when the pressure started to have it cut short and permed to make it 'neater', waves disapproved of, only certain shades of blonde dye allowed, full make up including foundation, powder, mascara, brown or taupe eyeshadow, pink or tawny pink lipstick. Heeled shoes with pointed toes, only a tailored coat unless it was a Chanel quilted style. Handbags were encouraged, as was the use of perfume to ensure that any smell of cigarettes was concealed. Not having pink nails and large, glittery engagement, wedding and eternity rings marked you out as being unkempt and fundamentally untrustworthy, so you were not allowed to go into the office where the men worked.
The PA was the only one permitted to wear 'prettier' clothes, as she was exempt from the rule of the office manager. She would therefore wear dresses or skirts that swished as she walked, cardigans, silk blouses, jewellery and have her hair down or wavy/curled. There was a minor commotion when she came to work wearing an ankle chain and had long, orange nails on return from a two week break in the Caribbean.
Smoking permitted at 11 and 2.30 breaktimes when the lovely cleaning lady would come round with the trolley and biscuits - this was essential even after redundancies because she had a mortgage to pay on her huge Victorian house in Zone 2 and the extra four hours meant she could cover it without having to get a second job cleaning a school in the afternoon. She earned about £3/hour.
Eating anything other than biscuits had to be done in the break/smoking room. Nobody was allowed to work through their lunch. Obligatory lunchtimes and Fridays in the pub. And Christmas involved the entire office going out from 1.30pm - late to a posh hotel on the company. If somebody accidentally overdid it at lunchtime, betting was opened on whether they would faceplant into the desk or fall off their chair and at what time.
NHS c. 2005.
Men - shirt and tie, leather shoes. Jacket could be placed on the back of a chair in an office and sleeves could be rolled up in summer as long as there were no visible tattoos, but the jacket had to go on when walking around site.
Women - knee length dark skirt suit, tan or barely black tights, black tops were not exactly approved of unless you were of a faith group that expected married women to cover their neck and arms to the elbow and to cover their natural hair, a cardigan could be worn in airconditioned offices not public facing as it protected against any bra straps showing. No blouses with sleeves above mid bicep as it meant somebody might see a hint of bra or outline of breast. Heeled court shoes only in black or Navy blue mandatory and it was a disciplinary offence to be seen in trainers at any time on site, including before and after work time. Only biologically possible hair colours allowed, no nail varnish, 'natural' full make up expected, a single item of jewellery in addition to a wedding or engagement ring, hair must be smooth and tied back at all times unless above chin length. Only one lobe piercing permitted. Any woman below the age of 40 was to be prevented from speaking to a doctor inside their office or consulting room at all costs. Unless they also had short cropped hair or were aged over 70, trousers and flat shoes were strongly disapproved of. Animal print would have been a serious clothing standards emergency. Must never been seen to be eating, but expected to stay at your desk through lunch. If the management meeting left catering leftovers (they always did), you could take them home but never eat them at work. If you went to the pub at lunchtime, you had to make sure that alcohol couldn't be smelled on your breath and you were quizzed as to whether you were there at the same time as any of the doctors (not because they were worried about them being drunk - that boat left sometime around 1845 - but because you might be entering into a liaison with one).
Education now.
Men - trousers, shirt, shoes, preferably clean and uncreased. Jumper for colder days. Often accessorised with a scarf when crossing the site. Black trainers will be strategically ignored outside Parent meetings. If your tattoos include a naked woman, please don't roll your sleeves up that high.
Women - we don't want to see more than the general outline of your boobs or your backside. So wear tights if your skirt is more than 4 inches above your knees, please. And proper, flat shoes or boots make it less likely you'll have your toes or ankle broken as Year 9 go thundering down the corridors. Don't expect any sympathy if a piercing gets caught and we'll ask you in private if you're alright if you look a little dishevelled, but will compliment you on anything and everything.
Other than that, crack on because we're just glad we managed to recruit you.