When my near-life feels completely pointless, and at the latest just before I cannot feed and/or clean myself, I intend to take steps to end my physical existence. Being heavily dependent on another is not likely to be a situation I will want to be in. Furthermore, caring for a helpless me is not something I wish to impose on my wife (she is eight years younger).
In my suicide I wish to minimise violence to my being. For options such as inert gas, pentobarbital or salts, I feel there is not as yet sufficient evidence for reliability around peacefulness. Graduated fasting appears to me, currently, to be the best option; reducing food and water before stopping them. Also, this seems closer to release than termination, and on the evidence not as challenging as most of us fear.
I believe I have received guidance that fasting should be my way to go. On two occasions a moth settled on my desk, sitting motionless for several days till death.