I've also had trouble with late payment.  The problem can be organizational inefficiency, especially with larger organizations.  They have their own internal payment processes and schedules, and there are various people involved with the payment of your invoice. You can very easily have late payment problems on your first invoice not because the client is acting in bad faith but because of miscommunication or internal disorganization.

So I started asking for a deposit up-front, which would "prime the pump" so that all of the organizational miscommunications and disorganization would be dealt with before I started coding.  I've only recently started asking for deposits, so I don't have a large enough sample size to say how effective it is yet, though.

And as an aside, late payments generally don't bother me (within reason).  But for the first few invoices, it's impossible to distinguish late payments from non-payments so I'm generally pretty strict with new clients until they establish a solid financial reputation with me.

On Sep 26, 2012, at 3:27 PM, John Norman <j...@7fff.com> wrote: