Talk to Eye Specialist on Weak Eyesight

My eye sight is 0.75 weak for right eye and 0.25 for left eye. I am using the glasses but not on regular basis . I am a student so should I wear glasses all the time or only during my lectures? Also I have heard that once you start wearing glasses, your eye lenses adapt themselves to that glasses lens and then your eyesight will never improve. So please clear that wether glasses improve eyesight or just stop it from getting furthur worse? And how would I know if my eyesight is improved as it's just 0.75.