Depending on where I was I'd guess I could last 10 days until I reached the limits of my policy. Either way I'd be nervous about money running out.
And interesting question is at what point, and how much would one pay to make alternative arrangements, if it was evident TI was going to run out. Noting that alternative arrangements are often not covered by TI unless to attend a special event etc. Someone on FT managed to get to Paris on Eurostar, hire a vehicle to drive to Madrid, pick up on IB flight to Buenos Aires and QF allowed the use of the LHR-SYD ticket on EZE-SYD instead. (perversely I think many that frequent AFF & FT would relish a challenge like that ... not so for the average traveller)