As others have said - location is important. Do not go anywhere that is too cut off - you may be happy driving a car now, but what will happen if there comes a time you cannot do so. Buses, train, Doctors, Dentists, shops within easy reach. And, then whatever else suits you. Find out if there is an active U3A in the area - can provide so many interesting people to meet and things to do.
Then the actual property itself. Only you can decide what is important in that to you. If you are keen gardeners then you may want somewhere with a small manageable garden, but if not, you may prefer a nice balcony and a communal garden or local park.
Flats or bungalows are pretty much better than a house, stairlifts are okay, but are not the best answer. How many bedrooms do you requre, how many loos and bathrooms? Do you need a large kitchen, only you can make these decisions.
I live by myself and moved at the age of 62 years from the large Edwardian family house to a 1930's terrace. Had a lovely time over the next few years getting that just right for me. spent quite a lot of money - thought it was future proof. However, a bad fall, and ageing and I realised that I needed to go into an easy to run flat.
So moved again at the age of 78 yrs. Not a good time to go through the trauma of selling and buying - finally managed it -and am so very happy that I did so. Love my flat. Had two tick lists when looking for where to buy - the first was WHAT I HAD TO HAVE and the second was WHAT I WOULD PREFER.
My town I was moving to was determined by other factors. Thank goodness, I moved last autumn, cannot imagine how I would have coped in that house in London during this period.