We set up a Roth and Investment accounts for our two with our financial company and have my name on the accounts. The deal with them is we will contribute what we can every year but this is for their retirement. If they withdraw any money with out discussing it with us from these accounts, we will stop the contributions.
We also try to be generous to them through out the year, might not be cash but items they need or want.
Right now it works for us.
This is what I did several years ago (6 or 7) for my now 30 year old married daughter with 2 small children. I set up a Roth and Investment account. My name is currently not on the account but I have "trading authority". Why? She is intimidated by the investment process....for now. She also never liked Math. The investment account was money she inherited from my father so it isn't pennies. She also agreed to my involvement (trading authority) when she agreed to allow me to take it out of "Trust", otherwise it would still be in Trust. She knows she can walk in and get the cash at any time.
I have nothing to do with their daily, monthly or yearly W2 earnings or expenditures. But, I gifted her a percentage of my stock in the generational family business that generates K1 income with "verbal conditions" for saving a part of it. It is from that source of money, I route money to her Roth and some to her investment account...and she gets the rest without question.
There are reasons I do this I am not going to mention here.....just call them extenuating circumstances. However, it is becoming time for me to hand this piece over. She still is intimidated though.