7 or 14 or more days is appropriate depending on the circumstances. GERD is usually a chronic condition so long term treatment is fairly common and necessary.

14 days is to give the lining in your stomach and esophagus more time to heal. Every time you eat, your stomach releases acid that again digests your esophagus and stomach lining. If it doesn't heal (after yrs and yrs and yrs) it can turn into a precancerous lesion called Barretts Esophagus. So 14 days is better if you have no issues with the medication