A record has as long as it needs. A competition performance has three minutes, one take and a signal chain you do not control.
The chain is not yours
Between the console and the living room there is a broadcast limiter, a codec and a television speaker the size of a coin. Every one of those stages takes something. The mix that leaves the truck is not the mix that arrives.
The practical consequence: leave headroom you would never leave on a streaming master. Deliver to the loudness spec the broadcaster asks for, not to the loudest thing you can make. The chain will add the aggression for you and it will not ask first.
Mono is the real format
Stereo width is the first casualty. Wide vocal doubles, hard-panned percussion, reverb with a phase-rotated return, all of it either collapses or cancels when the signal is summed. Check the mix in mono early and often, not as a final box to tick.
If the arrangement only works wide, the arrangement is the problem, not the mix.
The low end has to be decided, not layered
Stadium PA and broadcast compression punish undecided low end. Two elements can own the bottom, not five. Pick which one carries weight and which one carries pitch and high-pass everything else without sentiment.
The first eight bars carry the vote
Attention is decided before the first chorus. The voice, the hook and the low end all have to be present and legible immediately. Anything that needs forty seconds to reveal itself will not get forty seconds.
What travels
The mixes that survive the chain are the ones that were simple on purpose: fewer elements, decided low end, mono-safe width, honest headroom. Everything else is a bet on equipment you will never touch.