It would be extremely unusual to see a ship without them. They include halyards, lifts, braces, and the gear associated with the gaff and boom on the mizzenmast. These lines are virtually essential just to keep all the spars in position. Some lines are used to raise and lower the yards and swing them around to receive the wind. Running rigging can be further divided into three sub-categories. and the sails in order to maneuver the ship. (Without it they'll fall over.) 'Running rigging' is the gear that's used to move the yards, gaffs, booms, etc. 'Standing rigging' is usually defined as the rigging that holds up the masts. There are several ways to approach the matter of rigging.
There are, fortunately, no rules in the hobby of ship model building.
One obvious point needs to be born in mind in any such discussion: it's your model and you don't 'have' to do anything to it.
