[christoph]

Tell me about it... sometimes I'm lucky to even have a PO (purchase order) number to put on the invoice, 30 days after I've completed the work with large companies.

The payments department won't even look at the invoice if it's missing that.

[cbsmith]

Rule number #1 in contracting: factor in the interest costs for N days interest in to your price. Your contracts should factor in an exorbitant penalty (based on time-value of money for YOU, not the market place) for post "net N" days (I'm a big fan of 10% + 1% per additional day). Great video on this:

http://vimeo.com/22053820