It used to be you could find a box of photos or keepsakes that you inherited to look back on how things were or when you were a kid. Now, most of that is stored on phones, and most parents probably don’t think to share or save them in a way to be passed down in the future.
I reccommend, and am certain many parents already do, to print the good photos and put them in a book.
Back your stuff up is good advice, in case the worst happens, but nothing beats physical books your kids can look through.
I bought one of those photo printers for this exact reason. Every once in a while, I’ll print some favorites and put them up in the house and in a photo book. It’s really nice to see them in physical form and not in my phone!
I’ve also given friends copies of group photos as gifts!
Better yet, back up to your computer, that is backed up to an external hard drive, that is copied to a trustworthy cloud somewhere. Always good to have duplicates should something happen.
I lost about 12 years of pictures after getting rid of OneDrive (getting rid of Microsoft cuz I maxed out the 1TB anyway), and no joke a few weeks later on my personal server, 4 out of 8 hard drives failed. Thinking it was my raid card, I replaced them, couldn’t get it to function. Apparently a storm that we had fried some components and not others, and I swear I had duplicates on some old offline drives, so when I installed those to restore, I did not have everything. Crushed my heart!! I bought a bunch of large flash drives specifically for photos and videos, and started to back up to those for historical purposes.
Just beware that flash drives are not meant for long term storage. Mechanical HDDs are the best of the regular storage drives.
The best is to truly keep multiples. But flash storage would be more resilient and durable. Mechanical is susceptible to mechanical failure, impact, electrical shortages, etc. Both affected by heat, but if both were in a safe, my money is on flash storage if it were the only option.