For those of you who have been practicing your art successfully, the question I am sure you are always confronted with is: what is my next step. I recently wrote about Growth vs. Expansion and will not rehash what I spoke of there, although it is definitely part of this discussion. The focus of this post is to ask why you should undertake whatever it is that you are thinking about doing next. The answer can't be that it just seems like a good idea. Not a bad starting point, but you need to do a lot more work BEFORE you commit to extending (and distracting) yourself.
The first question HAS to be -- will it support my core brand and will the endeavor's success bring success to the other aspects of the business. Presuming yes to this question, the next question is what is the purpose other than profit? Is the endeavor going to provide leverage for the business, allow you to change your lifestyle, or even sell the business? Leverage to me is another revenue stream whose product or service the business can use for itself and also sell to the public. For instance, an interior designer opening a retail store whose items he can use in his designs but also sell to the public (VW Home). Leverage is also about doing things that do not directly involve you as the artist (Laura Novak's Little Nest).
Selling the business is an admirable and worthy goal for any business owner. Whether you actually sell or not is irrelevant so long as you consider what a buyer might find attractive both in the core business and with what you are planning. The key will also be what growth they will be able to extract from the business that you can't.
I can say that if what you are planning, even after getting past the brand enhancement hurdle, doesn't give you leverage, change your lifestyle or set the business up for sale, then I am not sure why you would undertake it other than ego. Not to say that ego isn't a very powerful motivator, just that there are only so many hours in the day. Your creative business exists to serve you, not the other way around. Without purpose to your forays beyond your already successful core, you will be soon overwhelmed by the endeavor. However, with purpose it will be very easy for you to keep your eye on the prize so to speak and know if it is appropriate to see your way through the inevitable Dip or not.