Is there any specific period to take general medications? e.g., my doc usually prescribes medicines for 3,5,7,10,20, etc. days. is this a must follow?

Meds.- Instructions: Afternoon; Depending on ailments and treatments- medication dosage and duration vary considerably. Typically, post op medication is taken for x amount of days. However, an antiobiotic for Pneumonia, like Levofloxacin requires 7-10 to eliminate such a chronic infection. Pay strict attention to medication dosage, times to take meds. and duration of treatment. If in doubbt find another doctor.

Symptoms or specific: I classify meds in two types. Specific meds like a course of antibiotics are time sensitive. Meaning the time needed to kill off the germ is what is given & you should do so unless you are okay with it failing. Symptomatic meds are those for symptoms like pain. You take them when and if you need them for as long as you need them. There may be extra left over so you don't have to call for refills.