Yep I take xanax and klonopin on an as-needed basis, I have very bad panic disorder though and basically need them just to perform necessary tasks like going to the store at times.
I wouldn't say the medications themselves "interfere" with your life, it's the fact that they can't be used daily and can lead to tolerance that interferes with my life since I have to plan everything around my medication. I can't just spontaneously go out, I have to have notice in advance so I can take my medication a few hours before... that's really not the medication interfering with my life though, it's my condition that is interfering, hell if it wasn't for benzodiazapenes I would be in a mental hospital by now. Let me put it this way, if I had to take a pill everyday that would make me feel as great as xanax did the first time I took it but I would be completely addicted to it... I would do it in a second. I wouldn't mind being addicted if I could live a normal life, the problem is these things stop working for most people, especially if you take them daily.
As far as lifting, no I never noticed anything negative there, it did not affect my gains in any way... it makes me really drowsy IF i'm not active but as long as I'm doing something I'm fine. If you can function normally though I wouldn't recommend benzos, these meds are really a last resort. On average I probably take them about three days a week, when I first started Xanax I would take 3 milligrams and that would be enough for me to jump out of a plane, It really took away any and all anxiety, I could be myself. About two years later I now take around 5 milligrams and it doesn't have nearly the same effect, it works but I still feel a bit of anxiety. That's tolerance and I don't even take them daily, it just goes to show you that these things aren't to be messed with if you don't really need them.