For me, it depends on the age of the players.
For kids, I will delay starting the clock so that they can tie their shoes. During dead balls, I will even instruct them to tie their shoes.
For young adults, they should have figured it out by now.
If they ask for a time out, I'm giving it to them if the rules allow it (team control, etc)
(Off topic: I've never had a player ask if they could tuck their shirt in...
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