When I first opened my practice I did "assigned counsel" work in Family Court in a couple counties. Assigned counsel are assigned by courts to represent indigent people (who can't afford a lawyer) in certain kinds of cases. Family offense petitions in Family Court are an example.
I hated it for a number of reasons, particularly that the work itself is unpleasant, and also because of the billing process. The billing problems were simple. First, the pay was too low. When I started it was paid at $25/hour for out-of-court work, and $40/hour for in-court work. On 1/1/04, the pay went up to $75/hour for most cases for most work. I charge my clients $200/hour. I give breaks in some cases, but almost never to $75/hour. At that point I will sometimes just say forget it - let's do this pro bono.
Second, the billing process was too complex and frustrating. Too many forms to fill out and too many steps in the process of submitting them. I think people who do it a lot get that worked out, but I just didn't like it. I generally charge my clients up front, and keep track of hours and expenses on a simple spreadsheet.
Regarding the work, the participants tend to be more irrational than in any other area of law. I think it's because of the emotions involved. Personal injury clients, defense or plaintiff, never seem to get too upset. Criminal defense clients usually know they're in trouble and they're just hoping you can minimize the damage, or they want to take a shot at trial, but know the risks and accept them. Parents fighting over their kids get extremely upset, irrational and generally disregard the advice of their lawyers.
Also, to a lesser extent, the work is unpleasant because of the quality of the practitioners, with some notable exceptions. They are less likely to return phone calls or respond to a letter. In some sense, they are doing this kind of work because they couldn't get better work. And again, there are exceptions to this.
So since I don't like this area, I figured I could avoid doing such work by charging a high amount up front. Few clients will choose to pay a large sum up front. As an example, for divorce cases I tell people $10,000 up front. That's worked so far. No one has been willing to put that much up - and I'm happy about it. I recommend friends (who are high-quality) who usually charge less up front.
But then there's the problem -- what if someone actually puts up the money? My practice being relatively new, and not having piles of cash around, I have to suck it up and do the work. And hopefully soon I will need money less, and I'll raise the up-front amount even higher. Or I'll hire an associate to handle this area.