[gesman]

This is the Key #1:

"How much would the company need to sell for before my equity has value?"

Key #2 (not mentioned ANYWHERE): "Can you guarantee that my equity will always be worth at least that in case of acquisition for the above value?"

Key #2 stated in writing (congruent with typical verbal promises of implied future wealth) will actually protect you and possibly justify your salary sacrifices.

Without Key #2 guarantees - the next round of funding will likely push your equity value out of existence.