This came up on another thread but it brings up something I've thought about for some time. Would it make sense for USSF or FIFA to codify laws for all age groups pertaining to field size, ball size, length of halves, substitutions, throw-ins etc? Seems like every club or tournament has their own set of rules for different ages and half the time nobody sure which ones to go by. Would save a lot of headache if we all had one standard to go by. Seeing how the overwhelming % of refs apply LOTG that have been modified for youths, perhaps this would make sense. Do other sports do this?