Today I found on medium this nice article by Federico Tenga about long term storing of bitcoin to be gifted to future generations.
There are a few interesting points to be considered, some of them I completely overlooked while thinking about this very topic:
So, have a read:
Recently Ive been tasked to gift some satoshis to a newborn baby, who is supposed to redeem them when he grows up, about 18 years from now. The challenge was trickier than originally expected, as there are many different ways to store bitcoin, each one with different trade-offs, and at the same time its hard to predict the state of the Bitcoin industry two decades into the future.
Hardware compatibility doesnt age wellAfter a few thoughts he came with this solution:

Read the whole article here:
He has an (inactive) account here on Bitcointalk, maybe if you have enough comment we can summon him back to the forum!