But just going equal salaries is often suboptimal.
Founder one is 19, has no-one to depend on him, can happily live for 40k a year.
Found two is 27, has a wife and a kid, has a mortgage, the lowest "stress" free amount he could live on is 80k a year.
So what are the options:
* Pay both 40k. Founder two cannot make end meets, and has to get a second consulting job on the side. He therefore puts less work into the product.
* Pay both 80k. This is "fair", but it is literally just padding the bank account of Founder one. You are cutting your runway N months short for no real gain in output.
* Pay one 40k, pay two 80k, give 1 a bit more equity. This can also be seen as "fair", but it may not be. Founder two is bringing 10 years of experience to the table. Founder one is bringing only two. So in the long haul, you are giving one more money.
* Pay one 40k, pay two 80k, give each equity based on what they bring to the table. Maybe founder one gets more equity. Maybe founder two does. Decent chance it would be founder two, as he has more experience.
To me the right play is pay people what they need to not stress, and give equity based on what they bring to the table. Obviously I am closer to founder two in the above scenario, and I suspect a few people advocating equal pay are closer to founder one.
At the end of the day, each founder is either worth it or not. Some wizard that lives in SF so needs 120k to live? Maybe he is worth it. Some guy with a party problem that needs 95k to live, despite being a junior dev? Maybe not worth it. I think it is better to evaluate each person and see if what they need is worth it, if not keep looking for someone else!