Should you always wear glasses or take them off when reading?

Sadly you didn't bother saying what your glasses were prescribed for and that makes all the difference in the world. If you were prescribed glasses for reading then of course you want to wear them when reading. But I sounds like you got glasses for distance. If that si the case and provided you don't have much of if any astigmatism correction then it would be best to not wear to not wear your glasses when your reading or doing other close work like sewing or something. But even doing that would only mean that your eyes may get accustomed to reading with your glasses and make it much harder to read without them.

Just as the others have said there is no written rule that says you must wear your glasses full time. If your vision is clear without them then you probably don't need to be wearing them except maybe when your doing close work like reading a book. Like you noticed when you went without your glasses for a week, at first you may get some small headaches which is just your eyes getting adjusted without them. But you may have to continue wearing your glasses when you drive if had them on when you got your license or had it renewed. So I suggest thatg once your very sure you can see just fine without your glasses you may want to go back and retake the vision test so you can have your restriction removed from your license. If your not sure if your restricted or not look at your drivers license and find where it says restrictions. If there is any letter, usually an "A", under it then your restricted toy wearing glasses and you don't want to get stopped and not have your glasses on.