A conductor I played for recently has a very different rehearsal philosophy from mine. I am really trying to make every minute that I spend on the oboe count. Even if I am playing Christmas schlock, I want to play it as though it counts and as though I care. It's part of my larger mission to make myself a better player who deserves a better job.
This conductor chooses music easy enough to play on one rehearsal with a professional but unspectacular orchestra. We rehearse once, on the day of the concert. He goes straight through every piece once, apparently uninterested in the missed notes and key changes, and barely shapes the phrases at all, and drops his hands the moment we reach the final note, as if a proper sense of finality is an utter waste of time. The idea is that we, as professionals, will take care of the problems ourselves, and meanwhile we won't be physically tired or emotionally spent at the concert that night because we've just basically "marked" all the way through the music. That frees us up to make beautiful music together in the performance, and allows him to make musical decisions in the moment, since he didn't over-plan anything earlier.
And this does work. We gave an exciting and fairly tight performance, and the audience was extremely responsive - they loved us! I guess my conclusion is probably that I need to lighten up a little bit. The result was good, and that is ultimately the point, and no one cares how sloppy we were in rehearsal as long as the concert is good.
But this technique is a risky one. It works for an orchestra that meets only a few times a year, because all the rest of the time those musicians are playing in other ensembles and really maintaining their professional standards. But if that were the only group I played in, and I got into the habit of sloughing through rehearsals, I suspect that that could become a habit in performance as well.
That's why it's important in my individual practice to stay vigilant about little flaws, and to really go for the big dynamics, the long line, and the delicate taper to the end of the phrase. If that homework is in place I can relax into the occasional throwaway rehearsal and not sweat our drastic philosophical differences.