I think there are lots of variables that make key differences, in my household costs were cut in a lot of obvious areas to make ends meet, we had a large allotment where we grew lots of fruit and vegetables and without that option the additional food costs for a family of 7 would have meant a regular second income would have been essential, we were lucky to be able to do that and some other families in a different place would not have that option so probably wouldn't survive on one income alone.