But at least I can see the purpose of overall sleeves - they do hold the wires together neatly enough. I'd hate to work with individually sleeved wires, on the other hand - all that those really do is add needless cost and bulk.
This brings me to cable bundling, and the various ways it can be done. Apart from sleeving, here's my own quick evaluation of (some of) the methods:
- "Zip" ties: Cheaply available and easy to apply, but difficult to remove and the protruding bit can get physically caught.
- Twist ties: Also cheaply available, and easy to apply and remove, but the steel wire inside them can present a short-circuit danger if its ends touch circuitry. I mainly use them to keep cables from getting tangled while stored.
- Ribbon cables: Cost-effective to manufacture and can save space with smaller numbers of wires, but not so much with bigger ones (as anyone who remembers parallel ATA/IDE or SCSI knows). (Although, I don't use the "rounded" PATA cables either, on the grounds that they may not meet the required electrical characteristics…)
- Twisting the wires together: Can work OK, but only as long as the bundle doesn't then un-twist. You may (or may not) gain some flexibility in doing it. I've split the poll option in two as braiding is preferable for 3 or more strands, but twisting may still be useful for 2.
- Braiding: Probably the best way of securely keeping 3 or more strands together without additional materials, and maintains reasonable flexibility if done well. The complication is in knowing (and applying) the correct procedure, which depends on the number of wires (and particularly whether that number is odd or even). (Although, don't forget that the sleeves most commonly applied to PSU output cables are themselves braids…)