Wealthfront has a great startup equity calculator post on their blog that's worth reading for every engineer who intends to work at a startup.
It has a few interesting data points, one of which is that Hardware Engineers tend to get more equity on average than software engineers. This could be because on average, companies that require hardware engineers tend to go for experienced hardware engineers, while it's not unusual for startups to hire new grads for software engineering work.
Rachleff also makes the point that it makes much more sense to manage your career than to manage your wealth. That's true for new graduates. It's definitely not true for people at the mid-point of their careers, which in Silicon Valley is a much younger age than anyone outside the Valley would believe. I think Rachleff understates how important proper handling of your finances are. After I left Google, I had the privilege of speaking to many people about wealth management. There were a surprising number of people who had more stock than I did with worse financial outcomes almost a decade later. The difference between having a good financial plan and trying to time the markets or relying on a crooked financial advisor are enormous!
In any case, a number of my clients implicitly understand this --- some of them have explicitly turned down multi-million dollar retention packages at big companies (or in some cases refused to even start negotiating for those) in favor of unknown outcomes at startups. Even if those startups do not succeed, the skills they learn and exposure to an environment that requires all their talents, rather than a subset of them, will eventually lead to far more success.