Doesn't then the question also become "can you afford to work at this work"?

Here's what I'm thinking.
Consider:
1. How much time do you have to devote to work, per year?

A. In the US, the standard calculation is a working year is 1400 hours. (It's probably about 1300 in Europe, but I'm not sure). Looking per year is a good idea because there are always slow and busy periods.

2. How much money do you want or need to earn in that time.?

Divide answer 1 by answer 2 to get a rough idea of what you need to be billing per hour.

But now...remember that
1. You need to pay taxes on your income.
2. You need to cover the times you work that has to be done but for which you aren't paid. An example would be the time you spend acquiring clients, but that's not the only one.
3. Whether or not you believe Moore's Law can be applied to programming and designing, you need a way to keep up with with changes to the type of work you do. You might need to beef up the amount of money you need to earn to reflect taking a course or two. Or you might add the length of time it will take you to learn new skills on your own to the "work for which you aren't paid" figure. Or both.

Recalculate what you need to earn and how much time you have to do it.

You could do this as:

all the money you need/(all the time you have available-all the time you will be working but not paid

Now, compare this number to the kinds of per-hour rates you've been earning. Look at the numbers over a year (or as much of a year as you have been working.)

Can you afford to be in business at the rates you're charging?
Can you afford to be in business at the rates people are willing to pay you?
Would you earn more money working at the local coffee bar (consider that unless you screw up you only need to go through the job search once, not every time you go looking for clients)


Not willing to do think about these things? Welcome to The Amateurs Club, friend.