class 4 felony

What is the name of your state (only U.S. law)? Arizona
I am being charged with possession or use of narcotic drugs, a class 4 felony and I don't know if I should hire a lawyer or if I should just take the one the court appoints for me?

This is a decision only you can make. There is a relevant adage, "You get what you pay for."

You should hire an attorney. A PD will not generally defend you well, they will get you a mediocre to poor deal.

Without further disparaging the under compensated and appreciated public / court appointed lawyers, let me point out, if you are asking the question, you most likely are not ELIGIBLE for a government paid-for lawyer. The public defender/court-appointed lawyer is for the indigent who can not afford a lawyer, not as some freebie default for those who are merely unwilling to pay for their own defense.