When do you know it is best to do long term disability?

when you cannot do your job correctly.

This is a difficult question - many people want to keep working for financial reasons, because they enjoy it, etc. When I made the decision to go on LTD there were many factors, but I will try to list the most important:

1) I knew I was not doing an adequate job. I was staying later and later and still not getting my job done. I made more mistakes. I could sense my boss was no longer confident in my work.
2) It took ALL my energy and I was unable to enjoy anything else

I think it's better to leave while you are still "ok" rather than waiting until you are asked to leave, or you are so fatigued and exhausted you have a tough time recovering.

Talk to your doctor. They'll be a valuable resource.

Hi,
I’m 47 and worked 18 years with ms... I just stopped working 6 months ago because I kept falling going up stairs and was overcome by fatigue and pain in feet... I knew it was time for me physically (of course not financially).... I was denied disability and must wait for an appeal. My job was very physical, but I also had cognitive issues at play. It’s reall not easy to say when it’s time to stop working because every person has different circumstances, but if it breaking you down physically you don’t have much choice. All the best and keep fighting MSERS

I retired (quit working) when I was in pain all the time, losing my bladder control, BM control. I realized I was out more times than I was working. I was no good to work, or to myself. Now, yes, I still have bad days, but, I am not worried about work. Just remember everyone’s MS is different. Talk to your doctor.
Lisa