i dont use them but as long as they are not taking away from action of the bait cant hurt. the one thing i do do in the winter in cold and especially cold and muddy water is keep a box of night crawlers on hand and break them into 1/4 inch or so peices to give a little smell etc which seems to help at tiems. again it cant hurt as others have said. think its more important in cold and or dirty water but im no expert in them as i dont use them in general other than nightcrawers on the jig at times