If you are get hurt or become ill and are unable to return to work, it's important to be realistic about how much money it'll take for you to live on. If you are eligible, benefits from Social Security disability insurance can play an important role in doing this.
Of course, private insurance companies may be all too eager to sell you various forms of coverage, before you become disabled. An income protection policy might be one of these possibilities. Long-term care insurance may be another. But buyer beware.
Let's say you were working and paying into the SSD system before becoming ill or injured. SSD benefits may be available. But keep in mind that the Social Security Administration has a pretty strict definition of disability for purposes of receiving SSDI. It isn't just that you are unable to do the work that you did before you got hurt or seriously ill. There are also two other parts of the definition.
One part is that you are unable to adjust to other work due to your medical condition or conditions. The other relates to the duration of your disability; it must last for at least a year, or be expected to either last that long or to result in your death.
Given this definition, it's only natural to wonder about partial disability. After all, it's entirely conceivable for someone to become partially disabled. This could mean that you are able to return to work, but at a job that yields a lower income than before.
For purposes of SSD, however, benefits are generally not available for partial disability, just as they are not available for short-term (less than a year) disability. But the system is complicated, and it makes sense to get professional advice about what you may be entitled to.
Source: "Disability Planner: What We Mean by Disability, SSA.gov