Just tell them you'll join on the condition that equity is on paper. If they're your friends, explain to them that it just makes sense to do this right away in order to focus on your business and prevent any greed or disagreements.
Imagine this hypothetical scenario: 1 Year from now, you have a decent amount of cash flow, and are steaming along smoothly. As far as personal income is concerned, you've all somehow survived on savings, credit, and a small salary. Now an investor comes up and wishes to invest, or say that you have a buyer or some other liquidation event. How will you split the harvest? Now each of the founders looks back and evaluates how much they feel they've contributed. Disagreements arise. The programmers claim that they built the product, the sales guys claim that they brought the income in, and ultimately, the legal owner with 100% equity gets the money and you never speak with each other again.
The moral of the story: It's easier to divide a hypothetical pie now than a real pie later. Get the equity worked out now.
Imagine this hypothetical scenario: 1 Year from now, you have a decent amount of cash flow, and are steaming along smoothly. As far as personal income is concerned, you've all somehow survived on savings, credit, and a small salary. Now an investor comes up and wishes to invest, or say that you have a buyer or some other liquidation event. How will you split the harvest? Now each of the founders looks back and evaluates how much they feel they've contributed. Disagreements arise. The programmers claim that they built the product, the sales guys claim that they brought the income in, and ultimately, the legal owner with 100% equity gets the money and you never speak with each other again.
The moral of the story: It's easier to divide a hypothetical pie now than a real pie later. Get the equity worked out now.