"I've definitely evolved, and I think that comes from just life experience. Every single song that I've ever written is just really from my real life, either painful or not, hopefully not nowadays," Stefani told CNBC.
Currently promoting her latest album, "You Make It Feel Like Christmas," Stefani said that when she looked back on her career she was nothing but herself.
"I definitely look back at myself and what I've been is just me. I haven't tried to be anything else."
"Every time I get to collaborate with somebody I grow a little bit, and you change a little bit with everybody you meet, and every experience you have, and every heartbreak, and every fall in love, and everything that you do," said Stefani.
"I mean every song that I write is just from my own life experience, so I just keep trying to be myself."
Beginning her music career in the 1990s, Stefani released a string of albums with No Doubt, before going on to release four solo studio albums.
Of her success, Stefani said that complacency isn't a problem for her.
"I don't think I have to really try to not be complacent, it's just always exciting," she said.
"I think it gets actually kind of more and more exciting and mind-blowing the longer you're around because you just keep thinking, 'It's going to be gone, it's going to be over, it's going to be done, they don't care anymore.'"