If you touch the end of the film, not on a frame, you will feel it sticky when it's still too wet to handle. You want it to feel smooth and slick, that means dry. Some films take 3-4 hours, some take more. A lot will depend on the environment you are drying it in and the temperature. My bathroom/darkroom stays about 23-24 degrees C and I have a home-made drying box to keep down any dust that may stick to the film.