Vocational rehab can really help you by helping match you to a job you are able to do and when you have this they can help make modifications that allow you to succeed. It is done with little cost to you; there isn't a cost unless they provide equipment and then it is really a small amount to help you feel invested in the equipment (this is as of doing this 8 years ago or so and in my state). In my case they recommended SSDI. I assume this recommendation helped me years later when I finally did do SSDI. At the time it was suggested I wasn't nearly ready yet but the same agency oversees SSDI applications and voc rehab in this state so it can't have hurt.

It does (again in my experience) take a while to get into the program and things moved somewhat slowly but in my case they had trouble coming up with recommendations beyond educating my employers who completely blew it off.

But it did help. I got a much better view of what I could do and what was hard and how that might be modified and what to look for in future jobs.