It was the polymath and American founding father Benjamin Franklin who observed in a letter, written in French to a friend, that “nothing is certain except death and taxes”. An endlessly quotable quote it may be, but it was really a throwaway line in a letter on the implementation of the US constitution.
Of course it’s not untrue, but there are other things about which you can be reasonably certain, so certain in fact that it makes good sense to plan for them.
For example if you have children, they will likely need to attend school and even university. It’s worth planning for that. Equally, there is a reasonably good chance that if you are a salaried employee, or perhaps run your own business, there will come a time that you will want to retire, and that if you plan for this properly, it is possible to have a fulfilling and comfortable retirement.