I think for a "minimum" time it would greatly vary depending on the people.
WHat about a "maximum" time? I mean in a hypothetical world if a couple had been dating for YEARS... and they both say they want to get married someday, but neither really do anything to get to that point (of getting engaged and married) is there a certain time when one of them would just be better off finding someone that won't take 547 years to propose?
