Tights are an essential part of a dancers gear. Personally, as a teacher, I discourage black tights on my students, as the leg becomes a silhouette and loses the three dimensional form by which I can better discern the action of the muscles. Ballet pink tights are perferred, while tan are acceptable.
Tights come in many different styles condusive to the style of dance class. A full footed tight with a slit in the bottom, called transitional tights and the best for class. The entire foot can be covered with access to the foot by opening the slit at the sole of the foot. Where pointe shoes are concerned, this type of tights are suggested. Thights with this style foot can be purchased to the waist or the more comfortable full body tights which cover the entire torso and have shoulder straps instead of a waist band.
When legwarmers are used, dancers must also be reminded that although they are keeping the muscles warm, they cover up portions of muscles that should be viewed by the teacher. Legwarmers can create a false warmth. It is possible to do barre in them, but the dancer can become too warm in them relying on an external comfort and misjudging it for the neccessary warmth gotten by their barre work excerises in the muscles of the leg itself. In general when the skin surface is cool, blood is pumped more rapidly thorugh the body and feeds the tendons in a natrual and healthy manner. Dancers can best judge this themselves. If after barre they take off their legwarmers before starting center floor work and find their legs suddenly cold and brittle, they will know their barre work has been an illusion…… no work at all.
Sweat pants also create all sorts of sloppy habits, besides not looking professional. The legs are not seen as they should be and corrections are missed.
Always go to Ballet Class properly dressed. You will feel better for it.