Apart from increasing cost with increasing age (e.g. over 60), one thing I've found when chatting to the companies is that as one gets older so they get more restrictive as well as more expensive. One company I spoke to has max time away from home limits for 75 and over whilst another wont provide cover.
I'm 66 so not affected yet (and a lot can change between now and then) and I suspect that as one gets older so you tend to find the more specialist companies who do not penalise. But it's bound to get harder as one ages.
Ian