You need enough coverage to provide you with sufficient income to live on until you are able to return to work or receive other financial resources (retirement, social security, etc.). The benefits you purchase through a Disability policy is quoted as monthly income that you receive if disabled. Consider your monthly income after taxes, now and in the future, as the base amount you would need. In addition to the monthly amount, an individual needs to consider the length of time you want to collect benefits, and when you would need them to begin.