1% equity in a $10M exit would net you $100k. Given a four year vesting schedule, that's $25k/yr. Since you're working for a startup, your salary might very well be much less than $25k/yr of what you're normally worth at other companies. Aggressively negotiating your salary at a non-startup company can get you that much and then some.
So it's about whether you believe the company will make a >$10M exit, knowing that most companies die and many exit for $10M or less.
It's also about other factors. For example, whether you get paid depends on liquidation preferences, and how much you get paid depends on dilution and taxes.
Also cost of living. I've heard that decent apartments in SF can go for $3k. (Zillow seems to confirm that many apartments are around $3k.) Compared to a $1,500 apartment in a place with reasonable cost of living, that's an extra $18k/yr that you'll need to pay just to live there. Actually, that's $18k/yr of post-tax salary, so more like $36k/yr of salary.