Here's why:
* She's a performer: Rachel is very conscious of her appearance and would likely want to look polished for performances. Nail polish is a common part of a performer's look.
* Her fashion sense: Rachel often wears bold and stylish outfits, and nail polish is a great way to complement an outfit.
* She's a girly girl: While Rachel has a strong personality, she also enjoys feminine things, and nail polish is a classic girly accessory.
However, we don't see her with nail polish as often as other characters, likely because the focus is on her singing and acting abilities.
Therefore, it's safe to assume that Rachel sometimes wears nail polish, but it's not a constant part of her look.