Let's say I am on vacation and I am thinking about if I have enough money to last until the day I go home: <br/><br/>"If I run out of money, I will go home early."<br/>"If I ran out of money, I would go home early."<br/><br/>Is it okay to use the hypothetical past tense, even if the writer is not certain about the possibility of an event happening or not happening?