Brass always wins the long game in my experience—plastic just can’t take the pressure (literally and figuratively). I’ve seen those “heavy-duty” plastic adapters crack out of nowhere, usually right when you’re least expecting it. As for plumber’s tape, I’m a three-wraps-and-done kind of person. Any more and it feels like you’re trying to mummify the threads. But yeah, leaving the valve open? I’ve done it out of pure laziness and lived to tell the tale, but I wouldn’t make a habit of it if you want to avoid surprise puddles.
I’ve got to agree—brass fittings are just less drama in the long run. I’ve replaced more than a few “reinforced” plastic sprayer adapters after tenants called about mystery leaks. The worst is when the plastic cracks right at the threads and you don’t even notice until there’s water pooling behind the toilet. As for plumber’s tape, I’m more of a four-wraps guy, but I get what you mean about overdoing it. And leaving the valve open? That’s playing with fire... or at least with wet floors.
Brass really does seem to be the way to go—those plastic adapters just don’t hold up, especially if you’ve got hard water or folks who aren’t super gentle with the handle. I’ve had a couple of those “invisible leaks” too, and it’s always a pain to track down. I’m usually a three-wraps-with-the-tape person, but I guess it depends on the threads. Leaving the valve open overnight makes me nervous... one little crack and you’re mopping up at 2am.