Insurance: If not already mandated by the state you are living in, buy insurance against catastrophic risk, that is any liability you are unable to pay without a major hit in your quality of life. This includes health insurance, liability insurance, disability insurance, legal expenses insurance if you are self-employed, rentor's insurance if your possesions are particularly valuable and life insurance if you have dependent children. If possible, buy insurance with co-payment as this reduces the premium massively. Again, anything that you can pay for without serious reduction in quality of life or that is a near-certain expense is meaningless to insure.

Also, insurance offers nice information and services. Liability insurance deals with mitigation and litigation for you, home owner's insurance informs you through the premium of particual risks of placing your home. They may even deal with the headache of finding and ordering people to repair your home.