I use a lot of sponsors. If I see my sales drop with all my sponsors then I know sales are just off for that week. If I see my sales drop with just one sponsor then that sets off a red flag that something must be up with that sponsor. I can say that 99% of the time my sales with all the sponsors that I am actively promoting stay about the same.
Sponsors want you to promote their stuff so it is in their own best interest for you to do well with them.
