most don't have VU meters.
0VU is a great rule, but if you track a tamborine at 0VU; you lose.
it really takes a bit of experience to know these things. You can't think that you learn program like Word and then be an Author.
Every type of instrument has its level.
With tape the problem was noise vs distortion and frequency response. You hit tape hard with everything (peak vs VU depending on the material) and used the line trim on the board to get the faders to look right and be usable.
The problem with some early digital was resolution, so you had to get to -2 fs on the peaks to get a good recording. If you compressed something to sound good and printed it to digital, you lost. Has to be done after in analog, don't know why there's no sun up in the sky.
At the same time the "direct to tape" phenomenon was happening, correct mic> good pre (even the console pre that have all been parted out and racked up)> Tape or digital Tape> console return> whatever you can get at after that> monitor.
Now you don't have to worry about noise, resolution problems don't really exist but you can lose yourself there, I do (but I have some really good gear).
My answer would be: Don't worry about it, make some good sounds anyway you can and capture them, make changes when you mix to your satisfaction, correct anything you can when you master and another project is done.
this a discussion that has been adressed many times and as I've seen on the remote forum, there's a sticky with the most dicussed topics at the top of the forum so any one who's loking can continue in the everlasting, never ending threads like these.
I've written the same response at least 5 times now.