Just a reminder: What you will get on an Internet forum is opinions, and sometimes they will vary wildly from one-another. In general, there are no right or wrong answers - just opinions.
Opinions are not without value but, in the end, you'll be making a judgement call.
Here's my opinion: In a perfect world, no dog would ever be left alone. My wife and I are retired so we're home a lot. On those occasions when we're both away, the two dogs (sort of) keep each other company. In the real world, and in our world until fairly recently, people need to work and most of us work outside the home. Many (but not all) dogs can eventually be given the run of the house but nearly all must be confined in some way until they mature a bit. A young dog explores the world by chewing on it. A mature dog may still chew on inappropriate (and sometimes dangerous) items - especially if they are bored.
Typically "crate-training" doesn't just mean putting the dog in a crate and letting them cry and maybe get used to it. The trick is the try and make the crate a happier place - possibly by feeding the dog in the crate (with the door open) or providing safe toys.
I never used a crate with my first four dogs, though I noticed that some of them would stake out a "den-like" place in the house where they could go for some peace and quiet. My black lab, for example, rearranged a bunch of seasonal camping gear stored under some steps and made himself a nest. We never required it, but he slept there most nights for most of his life. Eventually, we decked it out with a heated mattress and (try not to laugh) some pictures on the walls.
When we got a young Plott hound (a breed that was probably never meant to live in a house) we brought her home in a crate from the shelter and then stashed the crate in the garage. When she showed a strong interest in destroying the house and everything in it, I got the crate out and determined to acclimate her to it. Luckily for me, she took to it right away. I also took her to doggy day care 3 times each week so she could burn off more energy than was possible with walks and fetch.
At some point, she made it clear that she no longer cared for the crate. She did this by repeatedly busting out of it in ways I would not have thought possible and showing up in my bedroom, and I made the gigantic leap of faith and retired the crate. She was with us for another ten years without incident.
My point is this: Without the crate, she (and I) would likely not have survived the first few years of hell-hound behavior. I am by no means an expert at "crate-training" since my dogs that have been crated had no issues with it. But I know you want to make it as pleasant as possible and never, ever use the crate as a punishment.