我把开支分为两个部份: mandatory and discretionary. It turns out that, for the mandatory,we were able to find more ways to cut, we were able to spent $600 less a month. For the discretionary, we spent less than half of the budget. Maybe we should take a cruise ? I don't know. Neither of us really enjoy travelling much though.
Some of the saving came from overestimating of the cost of living in SoCal. Yes here the housing and gas are more expensive, but you spent much less in utilities as the weather is so good. clothes and groceries are also less. You don't need to spend much on gas when retired.
I also began to doubt about the 4% rule - it is probably too conservative. 5% will be just fine, especially we will start getting SS in less than 15 years.