I've always felt the sometimes time away can help. I'm a firm believer in muscle memory, and after having played for more than say..........ten years or so, a players body memorizes the stance, stroke, ect. I think that if you hit the practice schedule very hard, over time you can actually teach your body new and sometimes not so desirable changes or habits. When I feel this happening, I might take a week or two off, and it has helped me in the past. I'm a believer in the idea that during that brief time away from the tables, your body forgets the newly learned bad habits and kinda reverts back to the fundamentals that hope I've picked up over the years. I will say however, that time away has helped me to rediscover my stroke, so when I come back from time off I feel like the accuracy, timing, and stroke are there, but the feel for speed control usually sucks!
Dave