Between lumps, pain, ropy, dense tissue, irregular size, or a little lift, your boobs change from week to week based on hormones, stress, age, activity level, and even your coffee habit!
While your boobs are healthy, become familiar with what's normal for your breasts so that you can recognize what's maybe not normal. If anything concerning comes up, always mention it to your doctor. The key to the best treatment, is to address it as early as possible.