You've got three kids, so each of them should get 1/3 of your estate, right? Maybe. Maybe not. Often parents are worried that giving one child a lesser inheritance in favor of his siblings will make him feel unloved or like the others are the "favorites" of the family. The resounding favorite planning technique, then, is a per stirpes distribution scheme: to my children in equal shares. If there's three kids, they each get 1/3. If there's seven kids, they each get 1/7. No analysis. No long-term forecasting. But that's not always a great idea.
Your Kids Aren't Created Equally
Genetics and nature will sometimes result in vastly different outcomes amongst siblings. Some kids will be born with development or intellectual disabilities, and others may just not be "good at school". Regardless, this results in siblings having less than an even playing field in life, which means an equal distribution of your estate may not be equitable. If you've got a son who's a physician and a daughter in the Peace Corp, their needs for future income and assets are likely worlds apart. So, having a general understanding of how you'd like your kids to benefit from your life's work, rather than just have a default "equal" distribution, is in the best interest of everyone.
Your Kids May Have Drastically Different Needs
A disability, drug habit, or creditor issues may also impact how your kids should benefit from your estate. In the example above, your daughter in the Peace Corp may be struggling to get by and likely hasn't put much away for retirement. The physician son may have more money than he knows what to do with, or may be making just below the highest tax bracket threshold. If you were to leave your entire IRA, for example, to your daughter, it may result in just enough of an increase in her annual income to be able to stabilize her finances and establish a nest egg. If your were to leave that same account to your son, you may end up causing him to pay more in taxes than he receives in income from the account, putting him in a worse position long-term. Likewise, if one of your children has a debilitating disability, they will likely need much more support long-term because of their inability to earn a wage. Leaving your entire estate to a disabled child may prevent that child from needing support from their siblings later in life.
Don't just divide your estate into equal shares if the result will not be equitable to your kids. Take a deeper dive on the matter and do what's right for your family, not just what people expect you to do.