Useful? It has definitely been my saving grace when I first started. Since I was concentrating on doing the stitch right, or keeping track of where to increase / decrease, I lost count frequently. Not to mention your mind kinda wanders as you crochet... The only annoying thing with such counter is that you have to put down your work to fiddle with the counter constantly.
If you don't feel like spending money, or if you're looking for a less intrusive way to count your stitches, there are many free alternatives, right on your computer.
Free Stitch Counter Apps on Your Computer:
Because these online counters require just a hit of a key, you don't have to put down your work. I find it much more natural.
Chrome Browser (both of these can be added to your browser via the extension store):
Counter: A simple app you can add to your Chrome. Press the up (or spacebar) / down arrow to count up and down, and F5 to refresh the counter.
Simple Counter: Pretty much the same idea.
There are also some great apps out there for your iPhone and Android smartphones. We'll take a look at those in Part II.
Do you crochet in front of your computer?