Income does not always reflect the real level of resources available. A family's economic capacity, its security and spending power, are based not only on household income at a single point in time but also on savings and debts, on home ownership and house values, on previous earnings and future expectations, on the help that may be available from other family members, and perhaps on the value of home-produced goods such as food and clothes. This may make a substantial difference to real 'disposable household income'.