I don't think you can really generalise about this issue. It depends on so many variables. Some people have loving families and they want to recognise that affection when they die.
Others have children who have paid scant attention to their parents over their lifetimes, in which case I wouldn't consider them deserving of anything simply because they share your blood.
Should you spend all your money on yourself? Chrysalis has sensibly pointed out the pitfalls there, ie that we will likely be living longer into older age than the generation preceding us, and will need to pay for care either in an institution or at home in the latter stages.
Not being able to fund what you want or need will likely see you bundled off into some nursing home you'd never want to be in.
And if you want to remain in your own home, think about what it will cost to pay people to do the housework, shop for you, keep the garden etc, when you become too frail to do it yourself. None of us like to consider this, but it's reality.
I suspect also whatever habits we've developed throughout our lifetimes we tend to subconsciously hold on to in retirement: if we've always been a bit frugal, savers rather than spenders, then we're unlikely to suddenly become free, rash spenders in old age.
Personally, I'll be happy to leave what I don't need to the RSPCA where it will do a lot more good in fighting animal cruelty than it would if left to some relatives.
