I don't have kids so there's not such a concern about inheritance. The main thing isn't so much to be sure I'll spend it all before I die as to have a better idea of how fast I can burn through savings, accepting that there may be some left over that I can leave to causes I care about. The idea isn't to make sure I die with nothing but to feel more comfortable spending at a rate knowing I won't budget for living 20 years and then find I have 20 good years and another 10 years living in poverty because I spent it all.
In simplistic terms, if you start with $1,000,000 and have 50 years you can spend $20,000 annually. If you only have 20 years you can spend $50,000 annually. If you'll be dead in five years you can really live it large for five years. But you wouldn't want to be spending $200,000 annually having a great time only to find you had to make the scraps last another 45 years, but neither would you necessarily want to live on $20,000 only to die with $900,000 left.