The first thing I bought after purchasing my Bronica SQ-Ai (even before the film!) was a threaded cable release. For a photographer who loves long exposure photography, it's a must-have.
If you have used them in the past, you might know they can be a bit of pain: they are always getting lost, and they seem to break easier than an egg.
It's true: I can't remember how many times I had to retrace my footprints in the snow to look for a cable that decided that the great outdoors were a nice place to settle. One of them took me almost 45 minutes of walking in the freezing winter of Indiana (-15F!) to find it. Incredibly, I always find them!
While losing them is my own fault, but fragile cable releases are not.
The first cables I purchased were rather cheap, around $8... or less. I've already thrown away 2, and I keep another one that is broken as a backup. That third broken cable release was the moment when I said: "enough!".
Following the advice that Gregg gave me on the video "Bronica SQ-Ai kit: what's in my camera bag", I went ahead and purchased a Nikon AR-3 (link to Amazon.com).
The price at the moment was $21 (it's just $13 as I write this, so consider getting yours now!), almost three times the cost of my previous cables. It was completely worth it.
Several months later, I'm using it and it's still going strong. I don't treat it better than the other ones, it's just better quality.
If you were looking for a mechanical shutter release cable, look no further. It might seem like a more expensive cable, but it will save you money in the long-term since it will last much longer than the cheapo ones you can find online.