there is no set time. its all about variables. is bearing clean? superlubed? are you a weakling? how long is the string? there are to many varibles to name.
do you mean just sitting at the end of the string? or doing tricks?
Keep in mind that just at the end of the string would be something in the range of 10 min, for a good thrower.
But in the middle of trick combo’s you are going to be hard pressed to get 1 min. out of it.