This paper addresses the theoretical conditions necessary for some subject of study to survive forever. A probabilistic analysis leads to some prerequisite conditions for preserving, say, electronic data indefinitely into the future. The general analysis would also apply to a species, a civilization, or any subject of study, as long as there is a definition of "survival" available. A distinction emerges between two approaches to longevity: being many or being smart. Natural selection relies on the first method, whereas a civilization, individual, or other singular subject must rely on the latter. A computational model of survival incorporates the idea of Kolmogorov-type complexity for both strategies to illustrate the role of data analysis and information processing that may be required. The survival-through-intelligence strategy has problems when the subject can self-modify, which is illustrated with a link to Turing's Halting Problem. The paper concludes with comments on the Fermi Paradox.