My understanding is that if you break your lease, the landlord has a duty to re-rent the place/try to minimize his losses. As such, as long as he can get someone else in, you usually won’t have liability under the lease. I say usually because there are situations where you might owe, i.e. your rent was $x/month and the market will only bear $x-$200/month now. You’d owe the difference per month over the term of your lease. Hoping the landlord will find a replacement is harder to do “safely” in a down market because your unit might go empty for a few months and you would be on the hook for that time.
However, don’t think that you would be on the hook for the entire lease period just because you broke the lease. Didn’t you mention you’d be in a desirable area? This might be less of an issue for you then. Also, you can always advertise you place for rent and as long as the renter is suitable, the landlord will have a hard time turning the renter down. How is he fulfilling his duty to minimize his damages if he rejects a qualified renter? Be wary if he says anything about a lock-in/Cal civil 1951.4, but you still should be ok if you bring a new renter.
Also, a friend’s father always told people to not pay their last month’s rent and tell the landlord to take it out of the deposit. The deposit is for unpaid rent and damages, so this is not something hugely unusual to do. Some leases try to limit this though.
And of course as the others point out, you can mutually agree to anything you want with your landlord, either before you begin leasing or when you want to break the lease. I would just make sure to get it in writing.
