I work as needed. Payment terms are very straight forward. All projects are negotiated and a retainer is required for me to start a project. The retainer fee is dependent on the project.
Payment terms are open as long as it is within the Guru Guidelines. I do require a payment in advance as a retainer.
I have a minimum hourly rate. I can also work off of an incentive base program. My hourly rate will stay the same the incentives will be paid as milestones or on the back end.
I'm a stickler for being paid on time. I have to have invoices entered by the end of the weekend. In turn the invoices are paid upon receipt. I have direct deposit to my account which does take a couple of days. On time payments make people happy and keep things going smoothly. :)