As I don’t know when I will die, when I will need carers and if I will need to go into a home a really can’t do much planning.
Theres plenty of decisions to make, planning to do that can increases the chances of you staying independent longer as you age, and keep you out of the carer system until you really it, and generally make things easier for both you and friends and family. In no particular order:
Have you done a PoA? Statement of wishes in the event you are incapacitated?
Is your house suitable? Eg Is it remote? How long does it take to get a taxi for example? Do you live in walking distance of shops, pharmacy, post office, GP surgery?
Are there many activities locally for retired people?
Are there good public transport links - is your bus stop nearby?
Does your house have a downstairs toilet? Could the house be easily adapted if your mobility was reduced, eg rails, stair lift, wet room instead of bathroom?
Do you keep your house in good repair? Is it modern and well insulated or old and draughty and prone to random things going wrong? Is it cluttered with stuff or well organised?
if you got taken into hospital tomorrow unconscious, do you have a list of emergency contacts handy for the emergency services to easily find?
Do you make an effort to eat a balanced diet, keep active with both cardiovascular and weight loading exercise (even a daily walk helps). Do you drink in moderation only, are you a smoker?
of course, none of this guarantees a better old age, shit can still happen - just look at Dr Michael Mosley. But making the right decisions in middle age onwards will make it so much better in the event you do get to old age.