I started mine 2 years ago when I was diagnosed with breast cancer, and DH and I have just bought a pre-paid funeral plan each. We chose the option which includes a simple funeral - although my DH was all for just being sent off to the crematorium without anyone there - until I pointed out that the funeral wouldn't be for him, it would be for the people he left behind.
I have cleared out my 'stuff' and got rid of a huge amount of junk. We have both made wills. I have made a list of how to disperse my personal possessions, things that aren't worth putting in my will. We both have a box file with all the necessary paperwork/information in. I have written down everything my executor will need to know when I'm dead. Who my life insurance is with, the policy number, the telephone number to ring. What to do about electricity bills, council tax etc. How to contact my employers pension scheme and the information they will need. If my DH is gone before me, the name of my solicitor and how to contact them, how to register my death. I have printed out the information on probate, inheritance tax (there shouldn't be any), that sort of thing.
I am working on the assumption that whoever has to deal with things when I die will be paralysed with grief. I know my DH would go completely to pieces, my local daughter will definitely not be able to cope, and the burden will probably fall on the daughter who lives 6 hours away. With that in mind, we are going to have the discussion with my daughters, when they are next both with us, as to what our plans are and who will be our executor. My DH is not the father of my children and has his own daughter, but he has chosen to appoint my daughter as his executor as he knows it will be a task too far for his own, both in miles and emotionally. He needs to have that discussion with her
We are both elderly and not in particularly good health so it is sensible to get everything in place. I have also had to act as executor for both of my parents so I know just how awful it can be, and just how difficult it is when you are grieving. You also need to bear in mind that if you appoint joint executors there may be clashes of opinion and perfectly loving, reasonable people can act very out of character when they are grieving. Hence making sure our wishes are very very clear and appointing a sole executor. They can, of course, choose to delegate their tasks to a solicitor if it is too much for them.
My mother had left detailed instructions for her funeral and how she wanted her personal possessions dispersed, and a folder with all the necessary paperwork, but I still had to negotiate the quagmire of arranging her funeral.
My MIL arranged her own funeral with a pre-paid funeral plan as soon as she was given her terminal cancer diagnosis. She had very little in the way of personal possessions to leave and nothing anyone was going to fight over, so that part wasn't a problem. It was so much easier to deal with the immediate aftermath of her death, knowing that we didn't need to make any of the arrangements or decisions.
We have tried to do both, arrange our funerals in advance, and sort out our wishes for what to do with our possessions. We want to make things as easy as we can for those we are leaving behind.