Co-founder relationships are critical to a startup’s long-term success. Some may say that selecting a co-founder is akin to a finding spouse, someone who will be in the tranches with you for the long haul.

For solo-founders looking for a co-founding partner, here are some considerations on when an early team-member is ready to take on the role of a co-founder:

1. You’re impressed with their work so far
2. The individual makes a material positive impact on the company’s valuation
3. They have been hiring great people and managing them well