How long can a person be on ECMO?

Can you elaborate on the duration of a person's stay on ECMO? Is there a typical timeframe for ECMO support, or does it vary significantly based on the individual's condition and the severity of their illness? Are there any factors that could potentially prolong or shorten the duration of ECMO support? Additionally, are there any risks associated with extended ECMO use that patients and their families should be aware of?