I took a class this last week that reminded me of several fundamentals that I had forgotten to use. Brushing off old information to use in your current works can add to what you have been doing and make it seem new.
Seeking out friends to share your passions can recharge your drive and help you move forward. Taking classes is a good way to make new friends and create momentum that will carry you through the coming winter months.
The key to being a professional is about being where you said you would. Big show, dog and pony, county fair..... if you committed; you need to keep your word and be there.
No effort is ever wasted and sometimes we still have lessons in the art we haven't sold. Take the time and chance that you can apply new lessons to old images. If you ruin it, just let it go.