After itemizing taxes especially with the mortgage interest deduction you’d probably have to make a little over $100K gross to get the full credit. For example you could pay CA 4,000 dollars, normally get back 1,200 and then the tax credit would be worth 2,800 instead of 3,333. I guess the way to look at it is you won’t be paying CA taxes for the next 3 years but that might not add up to 10,000.
The other thing to think about is the stipulation in the bill that if too many people take the credit then the amount you receive will be reduced. I.e. the first time buyer credit can be reduced to a total of 5,700 or 1900 a year if too many people take it and the money runs out. There’s 100 million dollars for the first time buyers credit but it’s difficult to estimate how far that money will go because not everyone will get the full amount. I’d assume that once 15K to 20K homes are sold to first time buyers there will be some deduction in payment.