Wife quitting job to be stay at home mom

Do you have any advice for a woman who is about to leave a high-profile career in order to devote all her time to parenting and homemaking? My wife is on the verge of taking this momentous step. How can we make it a smooth transition? We've reached this decision together after hours and hours of prayer and discussion, but I still have questions and doubts. For one thing, how can I be sure that we'll be able to make it financially?