I had problems with the old challenge. I had set aside 2 hours a day to complete to complete the daily word count. Instead of taking 2 hours to complete it, it took 4 hours. I don't have enough spare time for 4 hours and I'm really out of practice with writing so I decided that 300 words a day would be better.
So next month I'll be starting the new challenge to do 9k words in a month. Unfortunately that means it's going to take nearly a year to complete the rought draft. Things are so busy these days that I have no choice. The days when I had time to complete 50k words in a month are long gone. I suppose I could still do it but the novel wouldn't be as high in quality.
I look forward to the new challenge. If all goes well I'll be doing again the month after that.