You're not legally obligated to tell your children what is in your estate plan. You could leave them everything or cut them out of the will entirely. You don't have to have a conversation with them about it. They don't have to agree with your plan. What you do is entirely up to you.
But should you have that conversation? It depends on your goals. If your goal is to make things go smoothly for your heirs, it may be wise to talk about it.
One reason you do want to talk to your children is if there is some extreme situation that is likely to cause conflict. Maybe all of your money is going to two children, but you plan to cut the third one out completely.
You can do that if you want. It's known as disinheriting someone. However, if they do not know why you did it, they may contest the estate plan. They may accuse the other heirs of conspiring against them, for instance, and manipulating you into cutting them out. This is known as undue influence. Whether they can prove it or not, this type of thing can cause a long legal battle that may make it so that your children never get along again.
If you sit down with the third child and tell them why you are doing what you're doing, you make a will contest less likely. You also make it so that they won't blame their siblings. They may still be unhappy with you, but at least they know where you stand and why. They won't be surprised.
Speaking of surprise, another reason these conversations can help is because you manage the expectations that your heirs have. What they think they're going to get may not line up with reality at all.
If they think they won't get much of anything and you really have $1 million to leave to them, it's a pleasant surprise that they'll enjoy. The trouble comes when they're planning on a massive inheritance and you don't plan to leave them one.
Maybe you don't have it. Maybe you do, but you're giving it to charity instead. Maybe you plan to leave money to friends and extended relations. Maybe you're going to put the money in a trust, so they won't get it all right away. Whatever you decide, if you think it will surprise them, you may want to give them a heads-up first so that they understand what's coming.
These are just a few things to consider as you make your estate plan, but you can see the impact it can have on your family. Be sure you know what steps to take moving forward.