I have an SEO client who is relatively well ranked (#2 on Google UK for his main keyword & top 10 for most others), who keeps complaining about what I am charging him.

I am happy that he is getting good value, but would like to know if anyone else out there does SEO in a field where there are also lots of affiliates out there. Typical affiliate margins in this field are around 10%, and I charge him much less than that.

Without going into too much detail about the situation, is there a general consensus as to what a fair performance based SEO commission might be?