Many states have legal medically assisted suicide, and some of those have relaxed restrictions on residency. This means that, with some hoops to jump through, and understanding that it isn't entirely elective (I don't think chronic depression will satisfy the constraints), you can travel to (e.g.) Oregon and commit a medically assisted suicide.
My favorite is the Sarco Pod, which seems an elegant, humane solution which is, unfortunately, not yet employed anywhere. To my knowledge, Switzerland - where it was invented - currently has a ban on its usage, and I don't know that its been exported anywhere yet.
There are a lot of potential situations where I'd like the option of having one last vacation with my wife in a lovely destination, ending with a visit up a Sarco Pod. If I'm diagnosed with Alzheimer's or other form of dementia; any of several forms of cancer; or some of the more nasty diseases like some types of scleroderma, where the pain receptors in your skin are firing 24/7, forever, and the best treatment available gives you cancer. Assuming that cures haven't been found, I want to be able to just end it before it gets bad.
I think it was Lindybeige who said,
[if I die], then nothing happens. I've experienced nothing; I was there for most of the existence of the universe before I was born, and it was fine.
Rather that than unrelieved suffering and financially draining every resource of my family.