I before E except after…..C. Old grammar jingle ...

...that nearly everyone remembers, yet it's loaded with exceptions

I before E except after C, or when sounded like "A" as in neighbor and weigh! Sleigh, inveigh, rein, reign, feign, feint, etc.

And then there's either, neither, weird, foreign, leisure, seize, height, sleight, protein, caffeine, forfeit, codeine, heifer....and chancier, chanciest, fancier, fanciest, financier,...etc.

The 'rule' is barely useful :p