Most skills are perishable.
Some skills are more important than others in a survival situation.
Two is one, one is none.
The previous three sentences are universal truths, but what do they mean?
Most Skills are Perishable.
Unfortunately, most skills that take any practice are not like riding a bike. The skills that can save your life when the situation takes a turn for the unexpected are absolutely perishable. They degrade over time, some are even lost as muscle memory and neural pathways forget proper techinique. This means you use them or lose them. Over the course of my career in the wilderness and in search and rescue and environmental photography, I have tied knots as a form of relaxation, something to kill time. While there are only a core group a knots you really need to know, their variants and how they are correctly tied are as helpful as more tools in your toolbox. If I go for an extended period of time without practicing, my knots become sloppy and take longer to tie. Deteriorating weather and failing light are not the time to realize you have forgotten this essential skill.
Fire is Life.
The ability to start a fire is second to maybe only analog navigation. I try to practice fire starting at least twice per season. As the seasons change, the available materials to construct the various phases of a tinder bundle change in both quality and availability. On most excursions, I have three forms of fire starting: a ferro rod, matches, and a lighter. Friction fires may look impressive on survival shows, but they are nearly impossible to achieve, especially in the northeastern woodlands where I spend so much time.
Two is One, One is None.
This is the basic rule of redundancy and should be included in all outdoor and wilderness logistics. While I don’t suggest doubling up on all of your gear, it is advisable to make sure you have multiple ways to achieve important and life saving tasks.
Skills are something to collect, to work on during down times. YouTube is a great resource for visually learning new skill sets from knowledgable and reputable sources. As a member of the search and rescue community, I get to participate in classes that cover a wide range of outdoor skills from man tracking in the wilderness to ice rescue to psychological first aid, much of this information can be gained by research and instructional videos. You can never have too many skills and never be closed off to learning a new way of doing something. Agility and humility are the keys.