HI Ive been doing SEO for clients for a quiet a while now. And im slightly embarassed to say that my billing system is complete bullshit. Honestly I have no idea how to estimate how much to charge a client. Naturally I kind of guestimate based on the critical factors such as domain age, estimated required links etc . But really its all very rough. Do any of you guys have a more hard a fast formula that you actively use for quotations?