I have thought long and hard about this and have changed my approach from time to time. I tend to be a workaholic, and I have made a general rule to keep work at work and spend my days off doing things other then tattoo related drawing. I try and clear the visual tattoo clutter out of my head by spending time with family, going to a museum, seeing a movie or show, or just going for a walk/hike or getting out on my bike. I feel like this approach has recharged my intentions and inspiration more then when i use to spend every waking moment searching for reference and thinking about my clients for the upcoming week.
I try and have one day out of a work week (Wednesday for me, which is my Monday) where i sit down and knock out as many drawings for clients as I can. If that means coming in to the shop at 9am I'll do that. No music, no clients, no one else there yet. I just get out my references and start knocking out appointment drawings in order of priority. I find my brain and hand really respond to that kind of intention to just sit down and draw rather then trying to cram drawing time in between appointments and walk ins. And for those kind of appointments I try and have it all work out and ok'd so when appointment time comes i can just sit down and tattoo.
I also got a really good tip from one of my other tattoo buddies to draw tiny. Like with a mechanical pencil to start with. Really little...like 1" x 2" no matter how big the tattoo is. Just to rough out a thumbnail of how i want everything to fit compositionally. and then once i like it in mini form I'll blow up that thumbnail and start working that way. It saves me so much time and energy. I'm not fully rendering things out that the client wants me to completely change. I show them the little guy and explain it to them and if they are into the idea i render it out.
Also I started having a day once a week were me and 4 other tattooers meet up and draw and paint for ourselves. No talking about tattoos, or work and the images can be whatever we want. We all just bring a bunch of supplies and see what happens. It's been great for inspiration and productivity.
Mario I think redrawing is okay if you don't drive it into the ground. I think artists need to tap into their intuition and go with what feels natural. I can always see it in my head and just try and get it down on paper. But i also always ask the imput of my co-workers "what looks weird? what doesn't work? how would you approach this?"
okay i feel like i'm rambling now........