Memorizing your seed phrase is absolutely an uncalculated risk.Seed phrase are to be written on several pieces of paper or encrypted on a steel and kept in a safe place.What do you think should be the essence why crypto wallets generate seed phrase,the reason is seed phrase that is also known as recovery phrase are mixed words it could be 12 or 24, they are used to recover wallet in case a user lose hold of his/her digital asset and crypto wallet.The best way to store your seed phrase is by keeping it safe offline(on a paper)and not online.Memorizing your seed phrase is nothing but stressing the brain that's meant to store other vital informations.
Yeah, and even if we can memorized it, sooner or later it will fail us as our brain might go hiccup and forget that one word and then it screw everything up for us. That's why this is not recommended, although I have nothing against those who try to practice it, but there is no fail-safe here.
So just write it down your mnemonic phrase and then hide or or protect it at all cost. And try to spread it, could be in your house, or even in a safety deposit box in a bank. And probably majority will agree to me that this is a very bad idea specially if you don't have a back up and just trying to put everything in your mind.