At your age, you have less to worry about than a younger person. Here's a link:

How Often Will I Be Reviewed to Keep my Disability Benefits | Disability Secrets

Excerpt:

" . . . those over the age of 55 are often assigned seven-year increments, simply because older individuals are less likely to improve than younger persons . . . "

Also, it is considered harder for older workers to be retrained for a new kind of work.