I was a single full time Dad with four kids. Two boys, two girls. I still have some of their stuff but lots of room and have several homes, plenty of space. Not really that much cargo as I bought them new skis, apple lap tops, etc, they took them and the old sporting stuff was fair game to repurpose with any kids that could use them. Like their soap box derby cars. 

The "stuff" will stay there as long as a parent allows it. Personally, I'd say when they get their own place. And if they don't have enough room, they can rent storage or decide what they truly want to keep.  

When they say, you need to get your "stuff". If it is not removed by X date, it will be donated or thrown away.  

More realistically what Miss Wanda Kubat-Nerdin - Wanda Can! said and perhaps not even then. 

Good question, Lise. When the family home sells, prompting a move into assisted living! LOL

When they move to their own home!

HaHa! I'm afraid I don't know - YET, Lise! I'm still 'storing' those childhood memories for both of my boys! 

I do joke that when Ray and I move to the beach to retire in a small condo, they'll need to come retrieve their belongings from our Charlotte home!!

If I did not make the gesture, their stuff would still be at my house. However, I will say this: Each took what they wanted & what was left, was safe where it was. That's what moms & dads do i.e., they provide security, liberty & such

Tell your friend to decide when the time is right for her!!

Children who grow up to be adults do not have the same desires for memorabilia as their parents do. I would tell my children (and I will at some point), hey, I don't have room for such and such, do you want it? If yes, I'll send it to you. If no, bye-bye. And then I'll secretly send it to their girlfriends. hahahahhaha

I guess it depends on how the  mother raised the kids and what her expectations are.  It might be good to let them know when they're growing up so they can plan for the future.  Many parents don't prepare the kids for adulthood, and continue to treat them like children, so they continue to act like children.

It stays as along as the parent allows it to stay. Most often it is when the parents time to move comes, then everything needs to go. Otherwise you know how much that stuff is worth? A good donation to retirement

I say just after graduation. I'm guilty of the same thing & gave most of it to my sister.

Our daughters have been gone a long time...in homes of their own. What we have that is still theirs is stuff that their mother values. When, sometime in the future, we downsize, that stuff will go...one way or another.

I guess when the space is needed.  I just got done clearing out my parent's house for renovation and found quite a few remnants from my childhood that I took home with me, haha.

Sooner is better than later.  I ended up packing the stuff and putting it under the tree, and sending as b day presents.  They caught on quickly and most of that stuff was trashed but at least they trashed it.  

They may be looking through all that stuff when they have to empty out the house after we die...

I think the kids should take what they want when they get a place of their own. What they don't want to take can be sold, donated, or thrown away. Mothers (more than fathers) tend to hold onto things as a nostalgic connection to their child's past.

Great question! I'll never forget the day that my father showed up at my house w/ my varsity letter jacket noting it was time that it lived in MY house.  It was our second house and I was probably pushing 40 at the time...  LOL

When they downsize and let the kids know that they need to pick it up or know that it will go into a dumpster.

Some just leave it in the attic and the kids find it when sorting through their parents estate.

I still have some of my adult children's things at my home. I need to let them know come get it or we will get rid of it.  It is long past time.

When my kids would come home for the holidays I'd ask them to donate at least 20 items from their closet. The first time they came home during the pandemic they did a big cleanout. I still have a few things such as American Girl dolls and some stuff in the attic. I guess those things will stay until we move.

Never.  I don't mind my children's things.  Although I have taken a few of my daughter's things that her sons like to play with.  Her room is my grandson's room at our house.

my home will always also be my children's home.  They can clean it out when I die.

As soon as they move into their first home. 

When they stop living there.

I took everything when I first departed.  It really depends on the parents.  Later on, in life whether it is downsizing or death it all goes somewhere.

Nothing new. Gather up the stuff left behind and box it.
If the box is not clamed in 1 year, (holiday visit cycle) send child a flyer announcing yard sale with his/her stuff featured.
However, viewing this from the greater message of Family Values, this 'kick out' trend in the USA doesn't seem to align.

Ship the stuff as soon as they have their own home.

Some people have the ability to tell someone to go to hell in a manner that they look forward to the journey.  It's a matter of whether you want to step on the doormat or be the doormat.

Some of these items could be highly collectible and valuable- so that's worth keeping in mind. When I was a teenager I was collecting 1950's and 1960's comic books. My high school had a comic book club and annual comic book convention. I reserved a table to sell some of my comics and nearly every dad would visit my table and tell me that they used to own these same comic books when they were a kid- but their mothers threw them out. Most of the comic books I sold I had doubled or tripled my money...and I only bought the issues 5 years or less- imagine the appreciation based on the initial sales price. 

My MIL packaged all of my husband’s childhood memories in a large fancy wrapped box and presented it to him for Christmas one year. By this time, he/we had established a family of our own and our kids (4-6 years old) were excited to see all my husbands “stuff”.

when they reach THIS point?

I'm mad as Hell...

After my father passed away and my mother was getting ready to downsize, , she called me and said that I could come and get my stuff or she'd put it in a truck for me to drive home.

I was kicked out at 16, so that's what I'm accustomed to...16 years!

No healthy kid should be home past 19 yrs of age.

I'll admit, I just cleaned out a few boxes in my parents' attic last summer and still have a couple of boxes left. They've been there since 2003 when I made my transatlantic move. It took a few years to - bit by bit - move my things over here. Sooo, I got a good excuse since I can't just load up my car. But I am very grateful that my parents have been so understanding. I am very lucky! 

When they buy their own home Lise Howe BUT they do have the opportunity to have it discarded, which my Pam would do eagerly...lol