Many people are counting on receiving an inheritance, therefore they don’t adequately make good financial plans. It isn’t unusual for some to not fund their retirement plans, because they think their parents are well off and will leave them enough money to live on. Parents though may not have as much money as we think they have, but they might just be really good at personal finances. On the other hand a lot of money might be consumed by health care in older age, or the parent might leave the money to a new spouse, skip you and transfer to your children, or might just not make good plans and the money is lost through mismanagement.
The Wall Street Journal had a pretty good article, if you want to read more about this topic, but suffice to say most experts agree that your financial plans should probably not take inheritances into consideration.