How long can a patient stay on ECMO?

I understand that ECMO, or extracorporeal membrane oxygenation, is a life-saving medical procedure used to support patients with severe respiratory or cardiac failure. But I'm curious, how long can a patient typically stay on ECMO? Is there a set timeframe for how long it's considered SAFE or effective? And what factors determine when a patient might be ready to come off ECMO support? I'm eager to learn more about the process and potential outcomes for patients undergoing this treatment.