When you create an address how do you know that this address is not already in use?
I know the chance is almost zero but still.
You don't know for sure. If this bothers you, you haven't bothered understanding actual numbers involved, and comparing them to other risks in everyday life. You should be much more worried that, the moment you try to deposit cash at the bank, a huge, red-green parrot smashes through the window, knocks down computer monitor, snapping the power cord in such a way as to electricute you causing second-degree burns and burning the banknotes you were about to hand over to the clerk. Also, you end up marrying that very clerk, but she dies from cancer only two years later.
