A year or so ago I was looking at retirement flats for my Mum (who was then 90)so that she could come and live near me. In the end, she couldn't face the idea of getting rid of most of her furniture and decided against it.
The sorts of properties she was looking at were one or two bedroomed flats in warden assisted developments. There was a monthly maintenance charge of, I think, around £80-£120. The flats she saw were quite small and all of them have similar layouts and fixtures and fittings - making them feel a bit old fashioned and "institutionalised". However, some developments are nicer than others - the ground floor flats in one development we saw had patio doors onto a small, private garden area, which was rather attractive. There is usually a laundry room with washing machine/tumble drier, and a residents' lounge, though these lounges didn't seem to be used very much.
I did look at the internet to find if there were comments regarding these retirement properties. Many of the comments were quite negative - the flats were apparently very difficult to sell (eg, if a person's health fails and he/she has to go into a home). They cannot be rented out to someone else and maintenance charges still need to be paid even if the owner is not living in the flat. I believe some companies also take a percentage of the sale price when a property is sold. There were also complaints about what some considered were excessive increases in maintenance charges.
I can see that the idea of having some sort of support as one gets older might be attractive, and not having external repairs to worry about as these are covered by the maintenance charge. However, wardens have only limited duties - mostly administrative - and do not provide individual support. On the plus side, there is obviously better security in such a development and the reassurance of knowing that all of your neighbours are older and not likely to be difficult or create a disturbance.
I would suggest you read up about it on the internet and also look at comments made by people living in these developments. You could also go and have a look at a few developments to see if such a scheme would suit your needs and try to speak to some residents. If you look at the Rightmove website, you can tick the box for "retirement properties" and maybe make an appointment to view one that is for sale. Obviously, if you decided to go ahead, you would need to talk through the contractual conditions with a solicitor and get his/her advice.
There are some very upmarket retirement "villages" that look really nice - but they are very expensive.
In Chingford, near to where I live, there is also a development where older people can rent a self-contained flat. The development also contains lots of amenities such as a restaurant and a hairdressers. It seems to be very popular. This would have suited my Mum but they have an upper age limit of, I think, 75.