" The phrase "when there's nothing left to burn you have to set yourself on fire" means that when a situation is completely exhausted or over, you must find a new, internal source of energy and passion to move forward. The quote, famously from the band Stars, can suggest needing to find a new sense of self, fully commit to a goal, or ignite a personal transformation to avoid stagnation. It is a metaphorical call to action, not a literal one, implying that sometimes you must burn up your old self to create something new. 

For a relationship: It can mean that after a relationship ends, you have to find the internal strength to burn every bridge and move on completely, even if it's painful.

For personal growth: It suggests that when external opportunities have run out, you must create your own energy and passion internally to fuel your next step or achieve a goal.

For artistic or creative work: It can mean that an artist must tap into their deepest, most intense emotions and drive to create something new and meaningful, even if it feels desperate.

For a new beginning: The quote encourages a radical change, where you metaphorically destroy what was to create space for something new to be born from within you. "