It's important to have the right watch size for your timepiece. A watch case size of 25-30mm is the typical case size for women watches. If you have a smaller wrist, 25-30mm might be the right fit for you too. If you're thinking of going with something in the 25-30mm category, you'll want to think about what case diameter, design or band width too. All in all, choose a size that you'll be most comfortable with.