What specifically does it mean if the prescription says 1 to 2 tablets 3 times a day as needed. Do I

You should only take the pills as needed, meaning take it only when you have pain. But, if your doctor does a urine test to test for the levels of the medicine in your body and it shows that you have very little to none in your system, he may believe that you're not taking them and may be giving them or selling them to someone. I'm not saying that you do this, I just want you to understand how the doctor may see it. What I do is if I am having a good week before my appointment and really didn't need to take too many pills(I can take up to 4 a day) a day or two before my appointment day) I take at least 2 to 3 pills a day and take one the morning of the appointment. This way if he does a urine test, it shows up that I am taking them. I hate having to take my pain medication, but when I'm in pain it can be very bad. I need my pain pills on those days to function.
Sorry the answer is so long, I just wanted to make sure you understand.