Yeah, we know "So We'll Go No More A-Roving" sounds a lot like a kid's song, but that doesn't mean it can't be about death. If a sword outwears its sheath, that's pretty much it for the sheath right? And if that wasn't clear enough, the speaker talks in the next line about the soul wearing out the body—in some religions, when the body dies, the soul leaves. So, it is about death. Now how does roving fit into all this? Well, the speaker wants to stop roving because he can sense that he's getting older, that death will eventually come, and he doesn't want to be roving around like a crazy frat guy when he should be doing more serious things leading up to the end of his life.
You don't have to be old to be worried that death is near. It's uncommon, but totally natural. Just witness Byron.
The approach of death can make us realize that we've been leading a purposeless, unfulfilling, and roving life. Gee, thanks Byron.
Ray Charles was right: "The night time is the right time to be with the one you love." That's what the speaker of "So We'll Go No More A-Roving" tells us, but he doesn't make it easy for us to figure out just what he means by love. Does he mean the night was made so great that he can't help loving it, or does he mean the night is a time for loving people—for chasing girls, having sex, making love, that sort of thing? It's probably some combination of both. And, by saying he goes roving in the night, and the night was made for love, he's also kind of saying he will love no more. Hmm, why not? Maybe he finally realizes that there are more important things to do.
Sounds weird, but loving can be a bad thing. The speaker still feels it, but he associates it with roving, and hence with something he needs to stop doing.
Love is associated with the night, and with lunacy (literally: moon, or luna, madness). In the first stanza, the speaker mentions love and the moon in the same breath to remind us of that.
You might be able to tell right away, but the speaker of "So We'll Go No More A-Roving" is no longer satisfied with his "roving." He acts like he's going to stop doing it, but we know better. All that business in the second stanza about things getting worn out tells us that he's no longer into his nightly romp. The reasons for his dissatisfaction aren't entirely clear, but his metaphors suggest that his something to do with getting older and feeling like death is coming. Time to clean up the party pad.
Try as we might, we're not always able to articulate why we feel dissatisfied. Take the speaker as an example; he never really gets to the heart of the matter.
Dissatisfaction is key to roving. While it may not be the most fun thing ever to experience, we'd never leave home without it (like American Express). It's the force the propels us to explore our world, just like it did for our speaker.