I always say that the higher they pay for your services the more likely they are to:
a)listen to you
b)respect your time and skills
c)do what you suggest they do
d)use what you build/create/write for them
To me the price I am paid is a measure of the attention, value and respect my work will get, and that goes for salaried work too.
If they know they dont pay you what you're worth they will abuse it, disrespect your time, and are unlikely to listen to your professional advice. There are of course some exceptions, but you'd better be sure it's an exception before you throw away weeks of your life on something that will never be valued...