How often can reflux flare ups last? I am just getting over one that lasted two months, and the last one was eight years ago.

Depends on cause. Gerd may reflect a # of causes: relaxed les (lower esophageal sphincter), delayed stomach emptying, partial outlet blockage from stomach, excessive acid production (like zollinger-ellison syndrome), poor esophageal clearance of acid (esophageal dysmotility, impaired salivation). Sometimes, its not acid that's refluxed so acid-blockers won't work well, or its biliary dyspepsia, eosinophilic, more.