Minimum lifespan for a sapient race

Although that's more a result of the appalling health conditions of the era. Humans that lived during the hunter-gatherer era actually stood a good chance of living to their late 60s if they didn't die in childhood.

Pretty much all old life expectancy data is going to be influenced by high infant and childhood mortality rate that drags down the average.

My understanding is that it was never that unusual for people who made it to adulthood to go on to live into their 60's/70's, but far more people didn't make it to adulthood.

Yea the average life expectancy of 30 is only an average (and also a neat demonstrator of why averages can be flawed). Generally if you lived beyond your teenage years you could easily become 60. it's just that with high infant mortality, famine and disease, the odds of actually making it past your teenage years were hard.

It's incredibly sobering to realize people had many, many kids and yet for thousands of years we were only a bit above replacement rate. Human numbers do not truly start to increase until the industrial era, with vastly more common medicine and hygiene.

But i think that's also going to be the greatest hurdle for any sort of sapient race -once developed into an industrial species they will likely see huge (average) lifepan increases, but you first have to make it there.

Going back to cephalopods, there are some things that can both grown, and more importantly, learn really freaking fast compared to humans. With than in mind, I could see something with a lifespan of about ten earth years growing to achieve civilization, especially on a planet with a shorter year and thus cycle of cultivation.