Hello Mark,
Welcome from North Yorkshire.
Again, not me personally but a good friend has had both hips 'done' - about 7 or 8 years apart. He was early 60s originally and last year (his last op) he was just into his 70s.
The first time he was worried he'd struggle with mobility, but he ended up walking as far as he always had. The last op was a little more worrying - he knew the walking would make it worth it but given the more advanced years he did worry whether his recuperation/physio would be harder.
He needn't have worried:- he is a great advocate for anyone considering such operations.
Now he knows he is going to be able to walk for many a good year (10+ at least) whereas without either op he would not be walking at all, literally.
Good luck and just think of how much better your walking will be afterwards.