I've never grown it before and the only other thing I've grown that gets woody is kohlrabi, which is pretty obvious. The okra I just picked (clemson) is like 5-6 inches long but I can still cut into it and it doesn't look woody. I have never bought and prepared okra either so I'm at a total loss here.
Early season okra is usually pretty tender as long as it get proper water. The later the season gets, the tougher the okra.... No matter how much water. I tend to pick it real small in the later parts of the season. I keep the pickles for myself in case they are tough. The smaller they are, the more tender they'll be.
If my knife meets any resistance when I cut, that okra pod is trashed. I've been so busy and tired the past few weeks that what little okra I'm getting is worthless... Time to plant some beans!
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.
Not all okra need be cut at a short length IME. Cultivars like Cowhorn and Louisiana Long Green can get fairly long and still be tender. However, I did find the finger rule to be true for Clemson Spineless. Nonetheless, you can't go wrong when using the finger rule.
I usually just cut them off when they are about 4" long. They slice easy into 1/2" long pieces like a banana. If they are soft and tender they are flexible like a hot dog. When they get woody they are stiff as a dowel rod.