You are confused what private keys are, and that's the reason you are asking the wrong questions in the loop which can't be answered. First you have to know what bitcoin private key is: It's any number between 1 and 1852673427797059126777135760139006525645401028465198470121682610264290583909392 . Nothing else. That number your computer chooses for you with random number generator can have many representations, decimal, hexadecimal or WIF, WIF being the one most commonly used because it has recognizable format, uniform length and checksum in the end to prevent typing or copy/paste mistakes. Problem is humans are vary bad at representing themselves how big 1852673427797059126777135760139006525645401028465198470121682610264290583909392 number really is. Illustration I've posted clearly explains that all computers which will ever be built can not collectively count to 1852673427797059126777135760139006525645401028465198470121682610264290583909392 before the universe colds up billions of years from now. So the simplest answer to your question is that we have so much time before anyone stumbles to your private key by accident that it can not be expressed in meaningful way humans can imagine. You have all the time in the world, planet Earth will probably turn into frozen rock before anyone finds anybodies else's private key.