The Rule of Thirds is particularly pernicious because it’s a sure-fire formula for getting it wrong. Just try placing something accurately on a Third and you’ll be dissatisfied and want to shift it a bit. I’ve never, ever seen an article on Thirds that did this. Close, yes, but close isn’t a rule. It’s the Rule of A Bit Off-Centre But Not Too Much.
The other “rules” are derived from Renaissance painting and architecture. They are useful for planning the work. (See, for instance, Modular, by Le Corbusier.) Ultimately, these systems were derived from close observation by intelligent and sensitive eyes. They were not arbitrary, like driving on the left or the other side of the road.
Photography is different. We can often make alternative compositions, each slightly different, or we can simply decline to click, which is tricky when you’re commissioned to build a Parthenon or Durham Cathedral or painting a Sistine Chapel.
There is one cast-iron rule: remove the Len’s cap. (Profuse apologies. Spell check won’t let me type L E N S . I have tried.).
I did hear of a customer who sued Wallace Heaton. (ah, dear dead days…) He’d bought a Leica for his once in a lifetime round the world cruise (it might even have been two) and they hadn’t explained this to him.
Happily for us, this is fairly unlikely in LF, although I have baffled myself by leaving the rear cap in place.