You only live once, but not in the context of how most people think about this phrase such as: party, drink, reward or entertain yourself. In other words, they justify some epicurean activities.
On the contrary, I use YOLO when I’m deciding to take on new projects, work, or tasks. My mindset is to create as many useful things as possible. Time is the only finite resource that we, humans, have.
Don’t postpone any longer something you wanted to do yesterday or last year. Time will pass anyway… So don’t spend your time on frivolous activities. Make your time count big time.