When it comes to options in lanyards, we as climbers, have many options that each bring advantages and disadvantages to our climbing. Some are more basic and technically "get the job done" while others are more advanced and can be used for various applications. With the days of free climbing in the past, and with different lanyard options available, every climber should be able to, safely and comfortably, position and ascend without ever disconnecting from the tree.
First and foremost is the trusted and true 3-strand adjustable lanyard. The 3-strand adjustable lanyard is exactly what the name implies, a lanyard made of 3-strand rope attached to 2 steel or aluminum snaps, tied with a prussik hitch to make it adjustable. This was the go-to lanyard for many years because of its affordability and its ease of use. With one moving part and no reason to take it apart, this lanyard was coveted by companies looking to outfit their climbers with a cheap and safe product. With every advantage, there tends to be tradeoffs. Where the lanyard shines in simplicity, it tends to lack in adjustability. Because the lanyard must be adjusted with two hands the climber would have to judge which length is going to be the most convenient before leaving the ground. The lanyard also adjusted typically from 3' to 6'. This general size would be great if every tree was a straight pole with no diameter changes but as we all know this is not the case. If the climber was using a closed climbing system, a 3-strand lanyard also opened the climber up to a major loss in efficiency because of having to tie in at every branch the climber met or free climbing for the time they passed over the limb.
With advancements in our industry came the 2 in 1 lanyard, which consisted of a length of 3-strand rope with a snap spliced on each end. Another snap was attached to an endless loop of 3-strand rope which then formed an adjustable prusik on the lanyard. This option ended the need to free climb since the prusik always stayed attached to the climbers side and each snap could be alternated over the next limb keeping the climber attached to the tree at all times. Though this advancement helped with safety, the adjustability of the lanyard still lacked with the need to be adjusted with two hands. If the climber was ascending a smaller diameter tree, the lanyard needed to be continually adjusted because of the design of the lanyard. If one side of the lanyard is extremely small, then the opposite side will be extremely long.
Climbers then moved their interest towards mechanical ascenders that could be used as an attachment point to their harness with a length of rope running through the ascender to work as the lanyard. These mechanical devices worked great because they could easily be adjusted, almost friction free, with one hand. The days of reaching around a large diameter tree and flailing to adjust your old 3-strand lanyard were over! These mechanical lanyards were also easily replaceable if your lanyard were compromised by a handsaw or chainsaw knick or cut. The device could easily be taken apart and the rope replaced in a matter of minutes, while older style lanyards would need to be replaced altogether. One disadvantage of the mechanical lanyards is their inability to be lengthened when under load. Because of the camming action of the ascender, the device cannot release the rope if it's under any sort of tension. Though this doesn't seem like a major issue, the possibility of a large limb ripping over and trapping the climber by their lanyard is still possible and should be mentioned.
Lastly, is the lanyard system which incorporates the essentials of an open climbing system to your lanyard. With the use of a length of rope with an eye or snap spliced to one end and a prusik / micro pulley combo for adjustments, this lanyard is easily the most versatile of all the options. The lanyard can easily be adjusted one handed and each part of the system is easily replaceable as well. Using the lanyard system as a typical lanyard is great, but this system really shines when used as a secondary tie in point. The lanyards are generally sold in longer lengths (14, 16, or 18') which makes them far more versatile than your typical 6' lanyard.
By attaching the adjustable portion of a huge lanyard to your center attachment point, the climber can put their lanyard around a far-away limb and attach the terminating end to their center attachment point as well. Once connected, they now have the mobility of a second tie-in point which makes positioning for some of those awkward cuts much easier than ever before. One disadvantage is in storing this longer lanyard. One option is to "daisy chain" the tail of the lanyard and attach it to the back side of your harness which works well, but is still more cumbersome than a smaller 6' lanyard. With all the options available nowadays it may seem difficult in choosing which option is best for you, but keep in mind the convenience and adjustability of some, with the simplicity of others. One option may be great for one climber while another works much better for another. Regardless of choice, always keep safety in mind and stay attached to that tree!