In my experience people were converted to an advisor status with any compensation only after they already provided sizable value and input. And initially they were really helpful not requesting anything at all. Good advisor is confident that he is good and does not want to secure compensation beforehand—if the advisor is helpful, startup would try to keep on board and motivate him.
Advisors should be excited about the company. To be able to work with a company they are excited about good advisors are willing to invest their time to show what they are capable of. I mean advisory is for people who already got successful and like to work with great startups they like. If they do it as the source of income, they are not good enough to be advisors.
Any advisor that requests compensation before providing any value is a hustler and scammer.