Oftentimes, at the end of an exam, your vet will recommend that you bring your pet back in for a recheck exam when the medicine is completed. Why is that? Don’t they trust the medicine? Shouldn’t I be able to tell just by looking if the medicine worked?
With some problems, like a cough, it is obvious when the problem is gone. Some are not so obvious. Just because Missy isn’t peeing in the house anymore doesn’t mean that the bladder infection is 100% gone. If it is not completely cleared up, the problem will come back soon, and may now be resistant to that antibiotic! Consider an ear infection: who has an otoscope at home to look all the way down to the eardrum to see if the ear is perfectly clear?
If the infection isn’t resolved, there may be need to continue or change medications. That is why it is important to recheck those urine samples, ear swabs, stool samples, etc. We are doing our best to make a problem go away and stay away.