One of the milestones of a growing small business is the point at which you decide you need a dress code. It was all in good fun when you were just a shoestring start-up in a tiny store-front, and there was just five of you running around in jeans and polo shirts. But now you have enough staff that making them conform to a uniform standard of fashion.
Sometimes, the incident is provoked by someone breaking what would be a rule, if it had been written already. The day somebody walks in in a get-up that raises your hair, offends a customer, or makes your visiting mother-in-law faint, that's when it finally hits you that you're going to need a dress code.
The key here is conservatism. The more public contact a staff member has, the more that employee should be treated as the public face of your business. While we do not want to micromanage every detail down to the height, in millimeters, of their shoe heels, we want to keep a definition of what is allowed as narrowly defined as possible. Nothing annoys employees more than the dreaded constantly-revised dress code, so you want to make up your mind at the start what you want to do and stick with it. Changing your mind every year will invite situations where you have confused employees showing up wondering why their tube top isn't acceptable today when it was fine last week.
Starting from the top, decide right away what is appropriate in hair style and facial appearance.
Hair - How long is too long? Are dyes OK? Remember that hair-dye is both a normal enhancement to change to another natural hair color, and a fashion statement made by young people who make it an outrageous shade of blue and green. Are radical styles allowed, such as mohawks and spikes? Try to find a balance that allows what is sensible and fashionable and disallows what is radical. You will also want to consider the new trend of shaving designs into the hair, seen on many young men with a buzz cut.
Facial decoration - Your male staff will want to know what, if anything, is acceptable for mustaches or beards. If you allow facial hair, be sure to define where the limit is in terms of style. For both sexes (these days) you will have to define the policy on make-up and facial piercings.
Trust me, if you don't think about specifically forbidding that people jam a crowbar through their chin, somebody, somewhere, will think of it. And they will come in and be all surprised when you send them home. On the other hand, social conventions about where, and with what, something on the face can be pierced are shifting to the point that radicalism is almost the norm. It doesn't make much sense to forbid all facial piercings when half of your customers will have them.
Tongue studs - This deserves it's own category just because it affects the speech. Actually, a tongue piercing that is done correctly should not affect the speech, but many young people throw caution to the wind and get a hole punched in the wrong place, then go slurring and lisping through life seemingly unaware that customers will have a hard time understanding them. You can always specify that piercing jewelry be removed before their shift.
Moving on to the body, there is the subject of tattoos. By this present time, most people understand that if they turn every visible inch of their surface into a walking art gallery, they will have a tough time getting hired. Most people these days have sense enough to keep a tattoo in a place not normally visible when wearing sensible business clothes. But you will want to specify your policy on this, if it is a sensitive concern. Remember that tattoos shock nobody in the 21st century, unless they depict a graphic image or words that are offensive.
Safety - In the restaurant trade, you will want to specify dress standards by function, taking into account things like OSHA regulations and Health Department codes. Working with machinery with moving parts necessitates forbidding wearing anything that can dangle and get caught, leading to an injury. Shoes should be worn that do not cause the wearer to slip, trip, or injure their feet if they drop something on them. Many positions will require gloves or hairnets or other sanitary gear.
Religious and cultural matters - Many people of a devout faith like to wear a necklace identifying their religious symbol, and there are also people from walks of life who identify strongly with their country of origin and like to wear something identifying their solidarity with it.
These can lead to some odd situations - there is an African religion in which joining the priesthood requires you to wear pure white for one full year, many Muslim branches require a certain amount of head and facial covering for females, and so on. It's up to you where to set the limit, here, but remember that when limiting religious or cultural dress items, you are running a risk of being accused of discriminating against a specific race or religion.
On the other hand, courts have recently begun to draw firmer lines between discriminating against certain religions or races and wearing outrageously blatant symbols and trappings or highly inappropriate attire while on the job. Here again, if you do not draw a limit, some one will find it for you. Also remember that you cannot favor one faith over another - if it is OK for the Christian and the Catholic to wear a cross pendant, then you also have to allow the Scientologist, the Jew, and the Satanist to wear symbols of their faith as well.
Lastly, remember to be only as conservative as you need to be, but no more than that. There is an acceptable level of individuality that you can use, usually based on what the general run of your customers will look like. For instance, it won't make sense to restrict tattoos in a biker bar, and you probably won't have much popularity if you restrict revealing clothing at a beach resort in the Bahamas. Also, we live in a more tolerant world now, and in fact letting your staff have a few tokens symbols of individuality can leave a favorable impression on some customers, who will like your business for being open-minded.