Single- and double-pin tracks

The difference is in the prototype.

If that level of detail is important to you, and you have a specific subject in mind, study photos to see which you need.

Single pin track is pin-link-pin-link..

Double pin track is pin-pin-link-pin-pin-link...

So whichever is more difficult is subordinate to whether that level of accuracy is important.

Bear in mind that the different types probably need different drive sprockets, so make sure that the track sets come with their sprockets, or see what the basic kit has.

Workable track means that it's like a watch band once assembled, flexible. Otherwise there are varieties of track like link-and-length that glue together in rigid sections.

Here I will give my opinion, only. There are several types of track systems on the real thing. Some AFV's have self tensioning track so there is no sag. Others have track sag, either between the return rollers such as on a Panzer 4, or one big sag such as on a T-55.

Other, primarily US tanks like the M-60; have no sag.

No sag- if link and length is available, it's simpler.

Tankskis- I like individual link.

Single pin is what it sounds like; one pin secures two links. An example is the T-34.

Double pin is where there are two closely spaced pins that are secured on the ends to hold the track links together, like on an M60.  Sometimes a middle connector with a guide tooth is also present.  So obviously a double pin track is more work to assemble.

I HATE doing double pin indie link tracks as it gets old really fast!

HTH

All of the above... with some detail differences. A single pin track has two links connected by single pins. A double pin track has two links connected by wayof two pins and separate end connectors. Track sag is often a result of being live track or dead track. Live track has rubber bushings inside the track pins to push back against the track sag, and dead track does not. Since before WWII, US vehicles have had live tracks on tracked vehicles. That is on vehicles not like  M2 and beyond Half Tracks that had a true “rubber band” track that were not composed of individual links. Most US AFVs since WWII have used a twin pin live track system, with few exceptions like the M113 and M2/LVTP vehicles which use a single pin live track. 

Real G

I HATE doing double pin indie link tracks as it gets old really fast!

HTH

i agree with the previous descriptions. Panthers abd tiger will have the T-55 sag unless they are turning. They lock a track to turn and it is a straight shot from sprocket to idler. BUT it looks bad on a model.

This is why i do a lot ofwarwheels though some suspensions are quite intricate and, with ww1 stuff, "delicate".