One other thing to consider is that some of these rules might be directed at the general public using cartridges that can barely track a groove even at 6-10 gms of downforce. In that environment, the stress placed on the groove is considerably higher and it may take longer for the groove to elastically snap back into its original shape.
Phono cartridges these days, even cheaper ones, are much kinder and more gentle than the crappy ceramic/crystal cartridges used in the past.
Phono cartridges these days, even cheaper ones, are much kinder and more gentle than the crappy ceramic/crystal cartridges used in the past.