Fend for yourself
Definition 1 of 2
Pro Tip 1/3Self-reliance
The phrase emphasizes the ability to manage without assistance. 
After I moved out, I had to quickly learn to fend for myself.
Pro Tip 2/3Economic Independence
Often used to describe supporting oneself financially. 
College students must fend for themselves with part-time jobs.
Pro Tip 3/3Independence Transition
Common when referring to a transition to adulthood or independence. 
At 18, most people are expected to fend for themselves.