We read in I Corinthians 11:15 that "if a woman has long hair, it is a glory to her, for her hair is given to her for a covering." Something that is a glory should be given special care and attention. Hair should be groomed and worn in a tasteful and attractive manner. If left on its own, it would soon become quite unattractive.
At the same time, one ought to keep proper modesty in mind. Some have gone to extremes out of vanity, which, of course, is certainly not God's will. In I Timothy 2:9-10, we find these instructions: "In like manner also, that the women adorn themselves in modest apparel, with propriety and moderation, not with braided hair or gold or pearls or costly clothing, but, which is proper for women professing godliness, with good works" (see I Peter 3:3). The "braided hair or gold or pearls" Paul mentions refers to a popular hairstyle of the day in which women piled their hair in an lavish set of braids interwoven with expensive jewelry, an attempt to proclaim their wealth and high station and incite envy.
Because Paul mentions long hair, some have been afraid to cut or style their hair at all. Notice, however, that I Corinthians 11:15 does not read "uncut hair"; it reads "long hair." The Bible nowhere prohibits tasteful cutting, curling, styling, or setting of a woman's hair. Any length is appropriate if the hair is long enough to be a covering and feminine. Any style is proper as long as it is modest and looks feminine.