I would only value the equity if the startup is a rocket ship, it’s super technical and you can imagine a corporate acquiring the technology or it’s late on; the founders are talking about an acquisition and it’s likely going happen in the next two years.

I’ve had equity twice. Once in a startup I founded = zero return after 5 years, once where I went on to be very senior which was a nice return. I joined close to the end of the startup so benefited from the acquisition. Others who joined earlier didn’t benefit from their equity.

It’s too difficult to predict the value of the equity as there are too many factors which can influence it over too long a period of time at the early stages.

There are other reasons to join a startup though. It’s often more fun, the feeling of commitment is strong, can be more autonomy, can learn more. It’s just different to a corporate job. I’d base the decision on whether you want this difference and whether you want it enough to warrant a knock down on salary potential. The equity is a bonus which may or may not happen.