Hope it's okay if I add a bit to this post...
I started my VA practice back in 2003. When I was just starting out, I made the BIG mistake of trying to be a "Jack-Of-All-Trades", trying to be everything to every client all hours of the day (and night). I did find a good deal of work, but found that it was exhausting me and it was so very stressful. I think I did a pretty good job at keeping my head above water, but looking back, I'm amazed I lasted my first year.
Since then, it's true what the others have said, I've learned to find what I really enjoy doing and have become very good at it. I do still offer a wide variety of services, because I think it's important to be versatile, but I consider them as the top 10 of what I'm really good at. I learned it's important to set strong
boundaries as well (ie: once I was clear that I am only available during business hours, things improved immensely).
I'm very comfortable now in my practice. I enjoy the clients I work with and feel the mutual benefit of doing what I love and doing it well. It's very rewarding and I'm so glad I stuck with it.
In a nutshell, trying to be everything to everyone isn't healthy for either the VA or the Client. If you can be careful of that syndrome, I think you'll do just fine.