The No. 1 reason why Americans save is to have something for emergencies. A survey by the Federal Reserve found that 35.2% of Americans save for a rainy day. That’s ahead of retirement (30.1%), purchases (11.5%), education (8.2%), family (5.7%), other (3.5%), to buy a home (3.2%). So, how much should you save for a rainy day? Opinions vary, especially for high-income households, but in general, the survey found rainy day funds should be between 9% and 14% of annual income. Put another way, most people think they need a little bit more than a month’s worth of income saved up.