In time an artist will ask him or herself as I did; how does one develop to widen and enrich your skill set and avoid coming to a dead end in which we are constantly repeating ourselves. I remember at one time seeing an artist on television who had just been discovered. The reporter asked him what the key to success was for an artist and his reply was to develop a unique style and stick to it. Many years later I saw him on the television again and saw that he was still doing the same thing. In nearly two decades it appeared he had stood still in his approach to painting. Whether this was as a result of his success and he was too afraid to tamper with a tried and true formula I don't know, but it did seem that the chap had never tried anything different.
It is a fact that galleries, critics, auction houses and any one who has anything to do with art but is not an artist will expect that the artist has a recognisable style. This is because, for them, art is a business and not a calling. Having a recognisable style helps them in selling the business of art and in talking the talk of art. So I asked myself why should I let the dictates of people who are not artists confine me to a life of having just one style.
If you paint the same subject the same way again and again you will become very proficient at it. However you will also learn only one way to paint and therefore limit yourself to a finite learning curve. There is nothing to stop you picking up a palette knife if you have only ever used a brush just to see what happens. You don't have to show it to the world and you can throw it away and start anew, each time learning a little more about the act of painting and creating art. If you have always painted blue sky try painting it yellow, or try an impressionist approach or any other myriad options available. For instance: try copying a classical masterpiece but paint it in a cubist manner. You will be surprised by what you learn about the complexities of the masterpiece by attempting to render it differently.
You will find that trying different approaches to painting helps you to develop and understand your main approach in more ways than by only ever doing the tried and true. I have found that my development over the years has come by learning from my mistakes. So don't be afraid to fail. You don't have to give up a recognisable style but you also don't have to limit what you can learn from trying new ways and you just might enjoy it.
Be ready for the criticism that by branching out you will become Jack of all Trades and Master of None. Again this is the voice of those who are not artists and don't understand the act of painting. The more you learn about painting the better you will become and the more your main style will advance. Trying new ways helps keep your enthusiasm for your art and will widen and enrich that vision. Forget the critics and curators, your art will be around long after they are not.