I play guitar and I'd like to grow out the nails on one hand for better picking. I'm also an avid swimmer. Would long nails get in the way or cause any problems?

Mostly it is going to depend on what kind of swimming your going to be doing. If your swiming in a public group enviroment then you will need to be careful around others as your longer nails could scratch someone. Also if your playing guitar then you will need time for your nails to harden after a swim as the water may tend to soften them temporarily.