Millennials and Gen Z are banking on an inheritance from their boomer parents. That's a big mistake.

When my husband's grandmother turned 87, our family realized it was time for us to take over her affairs. Grandma Sue was ailing and recently widowed, so we decided that it was best for her to turn over her finances. Between retirement savings and the proceeds from the sale of her house, she had about $250,000 in assets at the time. She told my husband that he would inherit all of it. On the face of it, Grandma Sue's generosity seemed like it would be a huge financial help for our family since the money was just about enough to pay off our mortgage. But my husband wasn't banking on a windfall.