It depends on what you define as practice.
I'm currently working on a stand-up copper silver transpo routine. I have tons of ideas of where the coins could go, how to transfer them back and forth and can do so well. Now that I have a dozen different things I could implement I've been spending today (at work) thinking of which ones would flow well together and create the most impact. I have scrap paper with notes all over it and even though I'm not 'practicing' I am working on my magic.
As far as sleight of hand goes, I have from 6-9 to do as much practice as I feel needed 3 nights a week while my girlfriend is in her CNA classes. I have time outside of those windows, but those are the best in terms of sitting and doing whatever I need to work on without fearing interruption.
I use my bathroom mirror, any given wall, and occasionally my video camera. I have my girlfriend and roommate to practice for, my girlfriend hates to know the secrets and my roommate has a bit of practice in magic so it's a good balance. I also tried out a lot of material over the holidays with family and friends which was good to get my new handling of OOTW, ace cutting sequence and routine, and a few other card tricks out of my practice sessions.
What doesn't work for me:: I can't go through entire routines until I've practiced each individual phase, move, and script until they're second nature. I could easily sit and switch two coins with the bobo switch 100 times in a row, paying attention to as much as I can while doing it, and not get bored like some magicians do. But if I'm going through a routine I might cover it 5 times before I get tired of doing it for nobody.
Just a few thoughts.