There are two forms disability coverage short term which normally covers the first 26 weeks of an eligible disability keeping you out of work.  Then there are policies available that can pay benefits up to age 65.

Most disability policies are purchased as part of a benefits plan for people at work.  Many policies, even through the employer, must be qualified for so you must be healthy before you make a purchase.

The maximum benefit allowable by law is 60% of your annual salary.

Keeping it simple, if you can afford this coverage buy it!  Do not wait until it is too late.