One study shows 78 percent of millennials would rather pay for experiences than materials goods.
The generation gap has spawned an entire industry of downsizing specialists.
Nan Hayes of Caring Transitions helps boomers and seniors figure out what to do with their treasures. She says it's often about emotional support, "We often try and get family members to help their parents through the transition."
The surplus of leftovers is leading to frequent new inventory at consignment shops and liquidation centers. That can translate into deals and steals if you're in the market.
"For the real bargain hunters: certainly they can find what they need," Hayes said.
Colacino said she would like to see traditions live on, "When these millennials are in their 60s they're going to say 'Hey, where's that that mom had? There was something dad always used.'"
She recommends taking what's old and making it new, "China is fun. You can have a dinner party. You can dress it up, dress it down. So what if it was your grandmother's best china. Make it fun."
Experts say no matter what you do with your belongings- if you're going to sell- know the value, and if you donate, make sure you get an itemized receipt for tax time.