If you are looking at sending your child to a private school, you're going to have to take a look at the dress codes at each potential campus. What your child wears will be a big deal in different ways, but overall, it will have an effect on how your child approaches the school day. The three major types of dress codes you'll encounter at private schools are uniforms, strict non-uniform dress codes, and relaxed dress codes.
Preventing Clothing Competition
For children, and especially pre-teens and teens, having the coolest clothing is a major goal. This can create resentment and feelings of isolation in kids who don't have the clothing or who can't afford to even think about having it. Going to a schools that requires uniforms can take care of that problem for the most part, but be aware that kids will find ways to create artificial markers of status. At a uniform school, that could include wearing a certain style of shoe, if the school allows different styles, or a particular cut of sweater. So your child won't be able to avoid the competition entirely, but it can be cut down by a substantial amount.
Another advantage to uniforms is that your child will always know what to wear. None of this "being late to school because he or she had nothing to wear" business.
Uniforms will require that you either have a lot of days' worth, or that you do laundry a lot. Schools that allow regular clothing, though, offer more flexibility in being able to improvise if the laundry hasn't been done.
One of the advantages to being in a school where regular clothing is allowed is that you have better control over the clothing budget for the year. With uniforms, you have to buy a certain style, often from a designated store. These uniforms can be a bit pricey, especially for people on a tight budget. With strict and relaxed dress codes that allow your child to wear regular clothing, though, you can choose where to shop and how much to spend.
Potential Tolerance Issues
One of the problems that has been increasing at schools where regular clothing is allowed, but there is a strict dress code, is that students can get sent home or shamed for tiny infractions. Often, this hits girls more than boys, or at least it can seem like it given the number of social media posts by outraged parents. A school with a more relaxed dress code may be best for avoiding this situation.
Should your child lose a piece of clothing, like a jacket, you'll find it easier to replace the item if you deal with more relaxed codes. A strict non-uniform dress code will be easier to fulfill in a pinch than a uniform dress code; a relaxed dress code will be easier to fulfill than a strict code. If you can afford to race out and get something quickly that fulfills the code, great, but if not, then your child can end up in trouble at school for violating the dress code.
Speak with school administrators about how they handle issues like low-income parents (whose children may be attending the school on a scholarship) trying to buy uniforms or students who violate the code by only a tiny bit (like a hem that's a half-inch too short). You want a school where your child's education will come first.