Lots of "which skins should I get?" threads keep popping up, so I thought I'd write something to bring those together.
There will be a few options as you start to look:
Nylon vs mohair?
Well, nylon is durable, sticks well on the skin track, and does so especially in the the "high traction" models out there. It's cheaper.
Mohair glides. It does so much better than nylon, but isn't as durable, and doesn't have the same stickiness on slippery skin tracks.
Mixed skins: these combine the attributes of nylon and mohair, typically in a 40/60 proportion respectively. They glide better than pure nylon on long approaches, but stick better and last longer than pure mohair.
Nylon tends to be the best for folks getting started, while pure mohair is generally the province of competent users or racers who can place their weight well. Mix options are a great middle ground.
Glue vs vacuum or similar?
Non-glued skins suck. Dodge them. You want a real glue on your skins, because skiing in the backcountry is messy, and vacuum skins use static friction that seems to fall apart constantly. There are laws in Europe that outlaw some of the (noxious) chemicals we are allowed to use in North America; this means that European Glues (Contour, most Pomoca) frequently don't have the staying power of their North American counterparts (BD is a good example).
Precut vs trim yourself?
If precut skins exist for your setup (like many K2 and Dynafit skis, for example), then the least hassle route is to use those. Make sure that your dimensions exactly fit what you're buying if it's precut.
G3, Pomoca, K2, BCA, and the BD Custom STS skins come with their tip and tail connectors preinstalled. This means you need to check their size chart to make sure your skis will fit a given size. You want to be in the middle of these size ranges--skins can lengthen a little when they get soaking wet, and some adjustability to keep your tail connector tight is a good plan. Also, if you have a ski with a particularly flat tail, that tail can press the tail connector parts of the skin into the snow with each and every step, causing extra drag, which sucks.
BD STS, Montana Sport, and Contour skins all come with preinstalled tail connectors, but you have to cut them to length and install the tip connector. This can range from some simple trimming and screws, to pound in rivets. Make sure to measure well here, and install them so that the tail connector clip is in the middle of its range.
How do I trim my skins? What is the acceptable range of gap?
First, there's a lot of variability in how wide your skins actually need to be.
People get by with a wide range of trim jobs, but perhaps the main issue comes with sidehilling, particularly in hard snow. If you've got a ski that's 100mm at the waist, and 130mm at the tip, and you get a 110mm skin, you're gonna have a little bit of gap somewhere where more base will be exposed. This is fine in fresh pow or flat skin tracks, but if you put your ski on edge in the hard stuff, it's gonna start slipping, and hard snow is exactly the place where slipping feels the sketchiest.
Personally, I've used a variety of different cut tolerances, and can say that I like having my edge, and only my edge (no base), fully exposed once I'm done trimming my skins. This exposes the metal to bite into a slope, but keeps traction near in every case.
Depending on the tools that come with your skins, trimming yours to fit your skis could be super easy, or more painstaking. If you're reusing a tool, likely it got gummed up by the last trim, so consider using a solvent to remove old gunk before you get started.
The supplied cutters with G3 and Pomoca skins (and similar) are excellent, and fast, and offset the cutting edge to trim the skin perfectly in one pass on each side.
Cutters like BD's take more time. Once I install my tip connector, I shift the skin a certain amount to the side, cut it on that side, then move it towards the other, leaving the edge plus one edge-width of base exposed on the side I cut first. Then I trim the second side, center the skin, and check my work. There are lots of videos out there--take your time to do it well.
Does a bikini trim help my tips from experiencing snow creep?
In personal experience, it does seem to help, especially if you've got a medium to wide sized tip connector.
Can I trim my skins a second time to fit a narrower, or similar set of skis to the first trim?
How do I store my skins during the season?
Skins don't like being wet. Start your day with dry skins, and when you get home, hang them up to dry in a place where the dog/cat isn't going to get fur all over them.
Once dry, fold them in half, or quarters, and stick glue to glue. If you like a skin bag, put them in. If not, fine. Either way, put them somewhere you won't forget them when it's time to go tour.
Cheater sheets take extra time, get in the way, and are frustrating. Personally, I never use them at home or in the field. Give them to someone who thinks they really need them (they don't).
While touring, I keep my skins in my pack, folded in half, glue to glue. Some people like to put them in their jacket pockets, or even down the front of their pants to keep them warm. If yours are iced up, this might be a good way to fix that.
How do I store my skins during the offseason?
I've heard all kinds of things, ranging from cheater sheets to keeping them in the freezer. Doesn't seem to matter much when I've tried these things. You can, and will, have skin glue run off your skins in a super hot car in the summer, so keep them cool. Mine live in a bin with the rest of my ski things, waiting for winter.
My skins are covered in snow on the plush side while out touring!
Glop is so annoying. Essentially, the plush is wet on your skin, and sticking to the snow it's sliding over. There's nothing worse than breaking trail through new snow that's rapidly being heated, as you can build up layer on layer of heavy, rage-inducing doom on the bottom of those lightweight touring skis you spent so much on.
BD's Glopstopper is a rub-on wax that helps a lot to keep your skins from glopping up. Do this early and often on those days, and it will make it so much better.
Rando racers and nerds will iron appropriate temperature wax into their skins, and then laugh at you when you're glopping.
One of my buddies treats the plush of his skins with Nikwax TX Direct Wash in, spreading it on the plush with a foam brush, then letting them dry. He swears by this.
My skins aren't sticking to my skis while out in the field!
Have you checked the tension of your tail and tip connectors?
Have you cleaned ice and snow from the glue? You can run the glue of your skins across the base and edges of your ski, or across the fabric of your ski pants on your thigh, to scrape ice/snow off or create heat/friction to heat up the glue so it will stick.
Are your bases wet? If it's gooey corn or wet snow, the more time you can give your bases to dry at each transition, the better they'll stick to your skins. I wipe water off my bases with a glove or sleeve, and point my bases towards the sun to facilitate drying.
Has your glue gone to shit? See below.
My skins really aren't sticking to my skis, and it's super bad, and I'm at my workbench.
Consider applying some spots of new skin glue in problem areas. BD's tubes of Gold Label are good for this.
Pick out debris like pine needles and dog hair with tweezers. Sure, it's boring, but this will help to clean up your glue.
Do you have ski wax stuck to your skins? Put a paper bag (lightly!) against the glue, and iron the plush (other side). This will get it gone.
Skin glue is frequently water based, meaning that over time, it will pick up water and become more gooey and less tacky. Take parchment paper, cover the glue side, and then iron the plush on the other side with your ski iron. The heat going through should help to reformulate the glue, cook out some of the water, and make it better in generally.
Consider regluing them entirely. The process is nasty, frustrating, and not worth it for me, but if you can find a hot scraper, and hopefully some glue-renew sheets, they might work. Might.
Is regluing skins worth it?
It depends. Personally, I value my time more than the effort it takes to reglue a set of skins.
Others would disagree, but here's another idea: get a new pair of skins, cut them well, use them hard, and then sell them before they are more than 60% thrashed for a good price. Hook someone up, get a new pair of skins, and keep enjoying uptracks and a nice piece of gear rather than being frustrated with it. My days off are too important to futz with easily preventable bullshit like bad skins.
If you're totally strapped for cash, regluing is the cheaper option.
The tips on my skis are huge, broad, and don't work with most tip connectors.
Yup. Moment, ON3P, and DPS all produce some skis that simply don't work well with many standard tip connectors. The two pivoting hands on the G3 tip attachment are the best solution here. Or, if you don't like G3 skins, but want to steal the tip connector, cut it off an old pair of beat skins and then seam grip and screw it to a pair of new BDs.
What skins should I buy?
These are personal suggestions, based on years of intense touring use, observed destruction, and some level of personal bias. Also, I live in the US, so that's some idea about the available options.
Something nylon. Precut is ideal. BD's Ascension STS is a great option (solid glue, durable, good connectors), while the BCA or Climbing Skins Direct offerings are also cheap.
Something mixed between nylon and mohair. BD's Glidelite is my personal benchmark (solid glue, generally durable, decent glide, good connectors) and I've happily used them for years for day in, day out touring.
If you're gonna walk a lot, really fast, or a long ways, you want mohair. It glides that much better. Montana Sport and Pomoca both make pure mohair options; the glue self destructed on my Pomocas in spectacular fashion. Still searching for a personal favorite here.
I'm sure this isn't close to everything, so chime in below.