Mine goes by what the regulations are for the state. If i'm using an earth anchor, 8" or less (law in NC) and if drag - I like 8'.
Heads up that in Maine you also have swivel mandates:
https://www.maine.gov/ifw/hunting-trapping/trapping-laws/regulations.html#specifictrapsRegulations for Specific Types of Traps
Foothold traps:
The statewide foothold trapping regulations are as follows:
Foothold traps must not be set above snow or ground level.
It is unlawful to use a trap with teeth on the jaws unless when set, placed, and tended, the trap is completely covered with water.
All foothold traps set on dry land must have at least three swiveling points and the chain must be centrally mounted at the base of the trap. One swiveling point must be at the base of the trap, one mid-way in the chain, and one at the trap's anchoring point.
3 Swivel Points
Centrally Mounted at the Base of the Trap
Think of this as the central third of the base of the trap anywhere within the circle. This can be a J-hook coming directly from the base of the trap or a swivel attached to the trap with D-ring, lap link or link of chain.
Midway-in the Chain
This is halfway between the base of the trap and the anchoring point. A double swivel (which technically has two swiveling points) is commonly used here, but another swiveling point is still required at the anchoring point and at the base of the trap.
The Anchoring Point
This is where the trap chain attaches to your anchoring device. An anchoring device may be a rebar stake, disposable or cable stake, or a drag. When using a drag, the anchoring point can be considered where the chain associated with the drag attaches to the trap chain. Remember that the use of drags is prohibited in WMD's 1-11, 14, 18 and 19.
