A few years back, Donna and I pulled up on a gravel point in Schooner Creek. She dunked her jig in PowerBait Bass formula while I threw mine out there with no scent. After she caught 4-5 straight keeper smallmouths while I went without a bite, I wised up and dunked my jig. Immediately, I began catching fish, too, and we ended up catching about a dozen total off that one point.
That is the only time since I started using scents like Fish Formula in the early 80s that I have seen it proven to work. But that was enough to convince me that I need to use it whenever I'm not too lazy.
Since the Power Bait is a spray, I really don't want the stuff all over our boat so I came up with this idea: Get yourself a normal-sized kitchen sponge and put it in a heavyweight Ziploc quart freezer bag. Pour enough of the scent (3-4 tablespoons) into the bag to saturate the sponge, then close up the bag and keep it in your pants pocket during the fishing day. Might not want to do this in tight jeans, but here's hoping most of us don't dress like that anyway.
To apply/reapply scent to your lure, just drop it into the bag, wrap the sponge around it and squeeze. Refresh the sponge as needed.