What will you do if the world does not end in the next 10-20 years?

Some Christians believe that the world's demise is close. I wonder what you will do if the end does not come within the time frame that you think it will come. I am a Christian who is not trying to judge others. But I wonder how people with such high expectations are going to react if the world does not end soon. After all, the Millerites were disappointed in the 19th century. Other Christians have been disappointed in the past too.