I left my room "as is" until it needed to be packed. I knew I was not leaving one single sewing item behind so I didn't have any purging to do.
My realtor thought it looked like a hobby room and said that potential buyers would recognize it as that also. It was messy as usual but I was able to be in there until the very last day which helped with my stress levels. Buyers could see enough of the room to see its walls, floor, closet, windows, etc..
So, if you have a dedicated hobby room I wouldn't worry too much about clutter. If the rest of your house is "show ready" then a lived in hobby room should be fine.