I realize that Joel Spoelsky has written an extensive summary of how equity should be allocated (namely, fairly), but I was wondering how things might differ in slightly different circumstances...
I recently joined a company that pivoted only a few months before I joined. The company was still gaining traction, with probably about 6 months of runway. There were about four founders when the company started, but has since whittled down to just the one founder (with about 50% equity). I effectively replaced one of the founders as the CTO, and have been given 10% equity.
In this circumstance (or similar), where original founders have left, and the company has effectively started over, how much equity should be awarded to new employees?
If you're not market rate, then it may be worth having "the talk" with your remaining founder regarding fair and appropriate equity. That said, a lot of posts seem to point to founding CTO as 10-20% (and most leaning towards the bottom of the curve) - others point towards 50 / 50%. Given that you would (likely) be considered a non-founder, the CTO numbers drop to 1-5%: but that generally assumes that the company has locked down the business model, funding worthy and in growth stage.
That said, there is no hard and fast rule regarding equity - It boils down to what is considered fair and reasonable. You should do your research, compare you position to others found online and present a fair and balanced recommendation to your partner.
Don't forget to consider vesting as part of the discussion.
Best of luck!