How long can you drive A car on a broken head gasket?

One man drove his car for 2 weeks with a broken head gasket before he blew his engine. Another drove it for 3 weeks. A head gasket costs several dollars if you can change it yourself. A new engine over a thousand. One mechanic can change a head gasket in an hour for $ 100. Other mechanics are no where near as good and take longer. It may be more in your area. How long do you want to go and how much do you want to pay?