text: This job - or that of an umpire - is something people often do part time, either after retiring from actually being a pro, or through a hobby that starts to take over.\nThe main requirement of course is to know the rules for your sport inside out and to the letter, and to be able to apply them.\nYou will need good judgement, be attentive to detail and able to deal with any conflict situations that may occur.\nThere is always high demand for this sort of role, though at the professional level competition is tight and you may have to work your way up gradually or have some 'in' to get your big break.\nThere can be good money to be made at the very top of most sports, but many perform this career just for fun and a few dollars extra income!