This ones kinda long but I think I covered just about everything
Care of Synthetics is much different than wire rope but just as intensive and important if not more important. This can go for synthetic winch line or tow lines. The biggest issue in chafing. Don't go sprinkling gold bond on it,. But mind it when dragging it in the dirt, or especially running it across rocks when under tension. Any abrasion at all and it should be repaired or preferably replaced. The best thing to do is to get a piece of non-synthetic chafing gear. To keep in you rig for when it has to rub on something. A 3 foot split piece of garden hose, or even a cotton sweat shirt would work in a pinch. Anything that the line can slide on without chafing. Preferably not something made of nylon or polyester as this will burn it.
* *Other things that cause chafing are dirt, ice, sand, or any type of debris in the line. Ice will reek havoc on lines. Moving the line with debris in it will cause chafing inside the line.
* *Things to maintain and extend the life of your synthetics. Wash with a mild soapy solution (car wash soap when you wash the heep) and actually scrub the line a little bit. This kills mold that can grow in line if it isn't allowed time to dry properly and the mold itself can wear on the inside of the line. Mildew also eats the synthetics.
* *After a long day of multiple pulls or an extreme winching requiring a lot of weight on you line, unspool the line and allow it to "rest." Synthetics stretch when under tension, but they don't return to there original size right away. So what will happen is you will spool it on hand tight then it will shrink and be stored under tension, and subtract from the life of the line. So I would recommend unspooling down to the last full wrap of the drum *and just hanging it on the bumper over night to allow it to shrink.
* *Also sun deteriorates all synthetics. Your winch line is probably a polypro based, or polyester based line so it will have less sun wear than nylon but still none the less it will degrade it. So get a cover for your winch.
So a short recap, wash your line, don't let it chafe on sharp objects, and store out of the sun.
Shackles are another important piece of rigging equipment, these can be used for all sorts of things on the trail, but like all pieces of gear need maintenance. Shackles should be made of steel alloy. Warn makes good ones, but I prefer Crosby red pin shackles. Allows are more malleable (meaning they stretch and bend before they break) this means they will show signs of failure before they break. This is important to us because often time we are pulling in tight quarters with people around, so if your shackle is failing, it will show signs before it blows up. The only real maintenance I perform on my shackles is I put a little bit of grease on the threads. They shouldn't rust easily but if they do just steel wool it off. And if it is bent or stretched at all float test it in the nearest large body of water. And for the most part if a shackle doesn't have the Working load limit stamped on it, or it says made in china throw it in the drink its worth the few extra bucks for the piece of mind knowing safety was in mind when it was made and it was tested to a certain rate.
One of my favorite pieces of equipment, but quite possible one of the most dangerous and misunderstood. A snatch block is a simple pulley, that's it plain and simple. Its called a snatch because the line doesn't have to be threaded through it and it can simply be opened up and the line placed in it. When winching these are great. They can be used when winching around a corner, and the small the angle the less strain is placed on the winch. For instance if you put a snatch block on a tree and then run the cable from your winch right back to your bumper it doubles the pulling capacity of your winch. If you are pulling around a corner and the line is making a 90 degree angle your winch has 150% the capacity. BUT. If whatever your snatch block is hooked to fails you just created the world most deadly sling shot. And now your 10 pd snatch block is going into hyper speed towards your buddy. So use this only if a straight pull is not safe or available and never let any one stand in the angle made by the wire rope. This is no joke.
* *Maintenance on these is simple. For it to work the shiv (wheel) inside has to spin freely, to determine this spin it with your fingers. Also check for indentations from the wire rope in the shiv. This is bad and shouldn't happen, it is cause by too much tension and not spinning. So I would just keep it well grease. And again clean. Also check that the attachment point is not worn or stretched.
Slings/ tow straps/ tow ropes
These are essential for winch less. Slings are good but they don't build up stretch to assist in pulling and they are quite a bit more money than the other two. These should be discarded if the polyester yarn inside is showing. As the yarn inside is actually one piece spun round and round if it gets torn the whole thing is useless and dangerous.
* *Tow straps and tow ropes. Synthetics: these are great because they stretch and then pop the stuck vehicle out. But if they show chafing or damage cut them up and throw them out. Its not worth the 30-60 bucks to kill your buddy.
* *Natural line tow ropes. These aren't as common any more but I have seen them used successfully. Manila line spliced at both ends makes a decent tow rope. BUT, it has nowhere near the strength of synthetics. It is also quite a bit safer than everything we have talked about because it doesn't shrink, or stretch so when it does fail it has no snap back, it typically just makes a big noise and falls to the ground. But caution and common sense should still be used. Drawbacks are, it rots, cant get it wet, and it chafes easily.
Things to keep in mind with all rigging equipment is the working load limit (WLL). Once you have all your cool new tools in action and looking sophisticated to unstuck your buddies rig, this set up is only as strong as its weakest link. So keep in mind that if you have a 12500lb winch with a shackle only rated to 4tons. You have a system only rated to 8000lbs. but your winch doesn't know that so it will keep pulling. The safety here is that most standing rigging(rigging that doesn't move on its own.) has a WLL of 50% the weight at which it completely fails. Running rigging( winches and rigging that moves on its own, typically stalls at its rated weight.) I wouldn't push my WLL's. this isn't a game and safety is the number one when dealing with anything rigging related. But when used safely and with common sense it is some of the most fun and rewarding parts of offroading.
Please keep in mind these are all recommendations from my experience in dealing with these things. I take no responsibility in any damage or harm that comes from using rigging gear as I have mentioned. Safety is the main key here. And should be exercised constantly. If you cant do it safely then don't do it and let some one with more experience do it.