It depends on you. If you feel your vision are not good enough for your work, learning and daily life, you can buy a pair of prescription eyeglasses. If you want feel the slight vision problem won't affect your daily life, you can not wear it. As we know, 20/20 stands for the best vision. And 20/25 and 20/30 us not as good. But, 20/30 vision is not a terrible vision problems.
That depends on yourself. 20/20 vision means that your vision is perfect and don't need any vision correction. While 20/30 vision is a little wose than the 20/20 vision. If you have 20/30 vision and can see everything clearly without glasses, then you don't have to wear glasses. If you find things far a way blurry when you view them, you'd better wear glasses when needed. However, you should go to see a doctor to have your eyes checked and the doctor will determine whether you should wear glasses or not if you have 20/30 vision.