If you spend enough time in the startup world, you start to recognise "life-stage startups": companies whose genesis lies in what the bulge demographic of founders is currently dealing with in life.

The cohort that was building food delivery and party-invite companies in 2014 is now building startups in early childhood learning, financial planning and mental health.

Personal experience remains one of the best reasons to start a business, and consequently life-stage startups often have deep customer insight.

But one mistake I see such founders make is to ignore the previous work done in the area. It's the startup equivalent of generational exceptionalism: "we're the first generation to fall in love/have a baby/have an existential crisis".

Another is not understanding the "narrowing of the funnel" with age. There are far more people with the same lifestyle and problems as you when you're 25, than when you're 45.

Partly that has to do with social and economic mobility: middle-aged founders disproportionately come from a group that has had more economic success than their peers. Sometimes this makes them distant from the needs of their wider generational cohort.

One hack I have seen successful founders use to cover their blind spots is to hire CXOs from a different generation - someone 10+ years older or younger who doesn't have the same generational bias and who can be more objective about the market opportunity.

It's fascinating, though, to see startup ideas march in lockstep with (so far) millennial life. As a new generation grows into adulthood, I'm looking forward to seeing them focus on the problems of 22 year olds again. :)