I don’t want to over complicate things, however if you have a lump sum calculated on your cost of living (which included your mortgage repayments) and (for the purpose of this example) this money is $1,000,000 which at your death is to be invested so that your loved ones were to receive an income stream from this investment of $70,000 per year, then it is imperative you also have an estate plan so that your wishes can be fulfilled.