Practicing songs VS Relying on inherent senses of music

I'm curious as to the value of practicing specific songs for different members on the forum.
For example, if you were to perform the song, how important would it be for you to practice it beforehand (given that you already know it fairly well)? This may seem like a fairly silly question, but I know a lot of good singers that can hear the backing track of a song and sing along to it almost perfectly even if they have never practiced it seriously. However, I don't feel like I can't do that. Actually, I know I can't do that right now. In order for me to get a song up to my recording or live standards, I really need to drill it and understand it.
To clarify my question, is it like that for everyone? Obviously anyone will benefit from practice. However, to what degree can you rely on your senses of pitch and timing to carry you through a tune you know in passing but have never practiced? Theoretically, having known any song well within my capabilities, I should be able to reproduce it exactly as I remember it in my mind. I don't know if I'm explaining this well enough.
For example, if you were to perform the song, how important would it be for you to practice it beforehand (given that you already know it fairly well)? This may seem like a fairly silly question, but I know a lot of good singers that can hear the backing track of a song and sing along to it almost perfectly even if they have never practiced it seriously. However, I don't feel like I can't do that. Actually, I know I can't do that right now. In order for me to get a song up to my recording or live standards, I really need to drill it and understand it.
To clarify my question, is it like that for everyone? Obviously anyone will benefit from practice. However, to what degree can you rely on your senses of pitch and timing to carry you through a tune you know in passing but have never practiced? Theoretically, having known any song well within my capabilities, I should be able to reproduce it exactly as I remember it in my mind. I don't know if I'm explaining this well enough.
Comments
Sometimes it can be disastrous, but that's rare, and the prospect of that makes it more exciting.
In a case like that, I'm willing to go out on a limb and do the song, just for the thrill factor. The audience likes it, too, if they know we're taking the risk of having a full trainwreck right before their very eyes.
It usually goes fine, and we emerge relatively unscathed on the other end of the song.
On the other hand, we never rehearse. We have about 6 proposed new songs, and I'm going over them myself, playing piano and singing them, to make sure they won't crash on my behalf. Several of these tunes are ones that are right at the top of my range, and I'm looking forward to doing them live. When we do, it will be the first time we've played these particular songs together as a band. I want to know my vocal part, because they're tough songs. The tough ones are songs that a year ago I would not even have been able to sing in the original key. I'm going over them myself to make sure I'm still comfortable singing these tunes, and it's all going fine at my individual practice sessions. That way I can do a decent job of paying attention to playing my drums and singing, because my drums are not set up here, and I will be playing drums and singing the songs live for the first time in front of an audience.
I do study the melody if it's a song with a lot of note bends and signature stylistic licks and nuances in it. Otherwise, if it's pretty standard stuff and the original version wasn't such a big deal, I'll do my own thing vocally.
We do hundreds of songs, so on any given night, I can be doing songs that I haven't performed for a year or more. My melodic memory and freedom to improvise are such that I enjoy the freedom of rediscovering tunes onstage without trepidation. I have fun with the experience of free-flowing musical direction.
Bob
We both feel that it adds a little excitement to the night for both us and the crowd!