2 ms·

Am I perhaps missing something in the OP question? What motivates you to invest eighteen months of free work for a commercial start-up? Friendship? Promises of

• zapu 10y ago
  Maybe the job was easy enough (takes little number of hours, OP mentioned "advising"), but is also interesting in some way and OP sees it as something that helps them grow. The prospect of significant returns after some serious investor comes in later - but if one was not compensated before, that is unlikely to change even if big money comes along.