Assuming we are able to find inhabitable planets and assuming we are able to solve the may physical problems of moving the human body through space for the extended lengths of time it would take to get to the nearest possible inhabitable planet (about 5,000 years away if our current space ships could go 100 times faster,) then the question would be --- is humanity ready to go to other inhabited or inhabitable planets?
Humanity should be finally ready when it can govern itself as a unified planetary community and live sustainably with enough for all on its own planet first.