I read that one of the best ways to preserve a seed phrase is to write it on a piece of paper and keep it in a safe place... Somewhere safe could be in your home out of the reach of family members and friends, it could also be a safe deposit box. But not everyone are financially buoyant to afford the services of a deposit box.
I believe we must have seen or heard about fire outbreaks, where buildings are completely erased by fire. Imagine if the owner or occupant of such a building has some Bitcoin assets, and has his/her phone, tablet, laptop and the seed phrase piece of paper in the building and everything was lost to fire. Now, this brings me to the question... Can seed phrase be memorized? It's advisable to memorize seed phrase?
It really depends on how good your memory is. If you have a bad memory and tend to forget certain things quickly, then I very much doubt your strategy of keeping your seed phrase in your head, will become something with a successful ending.
I personally am quite forgetful and I doubt I could remember my seed phrase for a long time. Maybe I could, maybe I could not, but that's not something I am willing to bet my money on. Better safe than sorry.
Whats wrong with a hardware wallet? They are really the most secure wallets that you can store your coins on.