Most SEO retainers max out at 30 percent margins because you are trading hours...

https://dibz.me/blog/why-a-handful-of-european-seo-agencies-stopped-being-agencies-and-1138

Most SEO retainers max out at 30 percent margins because you are trading hours for money. Turn your best internal workflows into a simple tool and shift your focus to 70 percent software margins. It is the best way to scale your agency.