There is no one answer for everybody, but you can guesstimate what you, yourself will need.
Write down all of your expenses for one year. Include everything...eating out, car repairs, medical bills, etc.
Then set up a spreadsheet that takes the total amount and adds 3% per year to that amount for inflation. To that add an extra $3,000 per year to cover surprise expenses. That's how much you will need to live as you are living now.
However, if you decide to downsize, etc, that figure can change.