I was surprised (at least for Birmingham/AL/Jefferson County) how accurately it pegged _most_ of the costs -- childcare here is closer to $12k/annum/child so that one was the only one I pegged as 'off' - they show 2 children as $16k and that's a ~$8k underestimate
I spend $20/month for mobile and buy a new $500 phone every 3 years.
I make way more than a livable wage, but spend much less than their projected costs.