Picking a co-founder tends to go like a shopping list. You can code, so you want someone who can sell. A technical founder needs a commercial one. Fill the gaps on the CV and you're done.
Simon Hay, co-founder of Firefly (sold to Veracross in 2024), thinks that list is optimising for the wrong thing. Simon spoke at a recent Founder Studio session and made the case that what decides whether a founding team survives its first real crisis isn't on anyone's CV.
Trust beats skills
Simon's advice on choosing a co-founder reversed the usual order. Put trust first, even though it's the hardest thing to judge early. Make sure you share a vision, because it's much harder if one of you has to keep selling the mission to the other. And look for a figure-it-out mindset over an impressive résumé. Most skills can be learned under pressure. Trust, conviction and the willingness to grind through ambiguity mostly can't.
Arguing well
Frequent debate between co-founders isn't a bad sign, Simon said. The skill is knowing which disagreements matter. Some are style, and not worth the energy. Others are high stakes and deserve proper time, even a proper row, if it leads to a better answer. As the company grows, keep most of that private and present a reasonably united front outside, so the team doesn't read disagreement as instability.
His test for a healthy relationship: can you argue hard and still trust each other afterwards? The bad sign is the opposite, where one founder is constantly having to persuade the other that the company should exist.
Protect the relationship before it needs repair. Don't let it become purely operational. Spend time together outside meetings and outside crisis mode, on a walk or an unstructured catch-up with no agenda. Resentment compounds, and it's much easier to prevent than to fix.
Slow down for the big ones
Simon's filter for how long to spend on a decision is simple. If it's reversible, make it fast. If it's irreversible or strategically important, slow down and debate it properly. Teams often do the opposite, agonising over reversible calls and rushing the irreversible ones because a deadline is looming. Sensitive structural questions like titles, role boundaries and reporting lines should be settled clearly and privately before they confuse the wider team, not left vague because the conversation is uncomfortable.
Advisors: start with a gap
The second half of the session moved to the network around the founders. Simon's advice was not to think of advisors only as a fundraising tactic. Ask what help you actually need (challenge, pattern recognition, mediation, domain expertise, governance) and be explicit about which one you want. Choose advisors for gaps in your own thinking, not for prestige, and try to get a mix: someone with a product or founder lens, someone with a commercial lens.
Use outsiders for real challenge, not reassurance. In his experience good advisors can also help mediate difficult founder decisions when the discussion is stuck. Treat the role as an active job, not an honorary title: advisor relationships can start informal, then formalise as the company and the relationship mature.
What a board is for
Simon saw the board as more than governance. Part of its value is the advice it gives, and part is that preparing for a board meeting forces sharper strategic thinking than you'd do alone. Keep it small enough to function, build it for complementary perspectives, not just investor representation, and where you can, set up healthy board habits before investor directors arrive, so you aren't improvising governance under pressure. Review the composition regularly. Advisors and board members have a shelf life, and a seat that made sense at the start won't stay right forever.
Raising money and angels
His fundraising advice came back to trust. Don't raise just because you can. Ask whether cash is really the limiting factor. If governance or advice is the bigger gap, build some of that first. Raise when the size of the opportunity and the competition justify moving faster, and treat each round as a fresh decision to double down, not a default next step.
On strategic angels, be clear with yourself about what you want from each one: money, advice, introductions or credibility. Don't assume they'll sell for you just because they wrote a cheque. His blunt observation was that customers rarely care who's on your cap table. The real strategic value comes from engaged advisors, not passive investors, however good the name looks on a slide.
A tension worth noticing
Simon's advice has a tension in it. He told founders not to over-index on complementary skills at the start, and also to be deliberate about role design and to hire specialists where a founder's weakness is clear and important. Read kindly, the two fit together: trust and shared vision decide whether you should start a company with someone, and skill gaps are a second-order problem you can fix once that foundation holds. But it's easy to blur in practice, and founders in a hurry sometimes use "we'll figure it out" to dodge a hard role or hiring conversation that structure would resolve faster than goodwill.
For founders
Before you commit to a co-founder, test trust and shared vision on purpose, through a real disagreement and not just a friendly chat. Once you're working together, get into the habit of sorting your arguments by how much they matter. And when you think about advisors, start from the specific gap in your own judgement, not a wish list of impressive names. The ones who end up mattering are usually recruited to answer a real question, not to decorate a deck.
