I believe now that the most important factor is that you should have one or two chairs empty of books etc so visitors can sit down if they drop in.And you must be able to eat on the table and get into bed without moving a lot of things like the newspaper you read before you got up or other odds and ends like face cleanser or tissues and stuff like that.
And you must keep the door keys handy in case you need an emergency exit.In fact I always unlock the back door before I begin to cook in case of fire!
Maybe keep spare keys in a definite place always.And some money in a box somewhere in case you need a cab to the hospital or the station if you decide to leave home in a hurry.
How my heart sings 
Good tip about the chairs – looking around at the moment, a surprise visitor would have a problem 🙂
I didn’t recognise the photo at first (I take too many!) but it’s the cultivar known as ‘Trewithen Blue’ and look lovely just outside my window.
I suppose if we think about it we can see what matters… that we can sit down,eat on the table and get into bed at night without moving too much stuff… cleaning is easier but being a bit more tidy is hard for me..
” cleaning is easier but being a bit more tidy is hard for me..” Yes, there’s always something much more interesting to do 🙂