Most people do not realize that there is an option other than filing for early retirement if one is physically unable to work. If you cannot reach full retirement age due to a physical/mental disability, you will (should) qualify for disability benefits that are paid at a much higher rate than the earily retirement rate at age 62. People who have a long work history and who wouldn't even think of missing work unless they were bleeding and on fire do not realize that the aches and pains they think of as just "growing old" that are forcing them to retire early are "disabiling". Social Security Disability is there because you have paid FICA (federal insurance contribution act) taxes that grow into retirement benefits. But, if you cannot get that far, full retirement benefits convert to disability benefits. People with a work history in California qualify for 12 months of State Disability Benefits if they are physically unable to work. That 12 months is usually enough for Social Security Disability benefits to start. Additionally, if you just cannot wait for financial reasons, you can file for early retirement and disability benefits at the same time. The rates will change however. Disability benefits are not charity. Sometimes the people who work the hardest see it as a hand-out or charity. It's not. You can think of it as "disability retirement" that some companies offer to qualified employees. Be smart. At least consider whether disability benefits are the right option for you. If you would rather receive less money, fine. But think before you jump right in to early retirement.
There are many factors other than how long you can sit, stand, walk, lift and carry that prevent people from being able to work. "Vocational Experts" testify about these. Some people have to be very close to a bathroom all the time and need unscheduled breaks. Some people have problems seeing anything smaller than a 50 cent piece, but their vision is other wise Ok to drive etc. Some people have terrible skin conditions on their hands that make it very painful to use their hands on a regular basis. Some people are required by their doctor to raise their feet to waist level. Some need to take rest breaks while laying down. A vocational expert will tell the judge that no employer will hire someone with any of those issues. Therefore, even if they can stand for two hours, they still are not employable. Your doctor needs to explain this to the Judge.