How long?

[toddhunter]

Tree straps?
Tarp RL
SRL
Guy lines
Suspension

[turnerminator]

6ft/10ft
35ft with Tarp Flyz and hooks
Dont use one
8ft corners and doors, 6ft middles
6 ft whoopies

[pgibson]

Each will depend a bit on where you hang and where you anticipate that you might hang. Tree straps from 3-20 feet per side with the average being 6-8 feet. Tape ridgeline most are good with 20-30 feet. Structural ridge depends on the hammock it going on. Guy lines for 6-8 foot though some use less and some use more this is a good overall length and is long enough to set up in poorch mode with trekking poles. Suspension goes to what type and ties in with the tree strap variables.

[hommes90]

Tree Straps: 14', or whatever the webbing is that came with my wbbb
Tarp RL/SRL: 42', with whoopie adjustment on each end, prussics for tarp and permanent loops for hammock
Guy Lines: 8' STLs for corners, 10' STLs for panel pulls

[Bubba]

Tree straps?
Tarp RL
SRL
Guy lines
Suspension

YMMV depending on your area and personal preferences but what has worked for me so far:

6 foot tree straps
12 feet of line from each end of my tarp
83% SRL
8 foot guy lines
6 foot whoopies