I use fluoro leader usually. I feel like I fish lots of shallow, clean water that's heavily pressured, with lures, so it has to look right. Seatrout and snapper can be picky in clearer water. Snook abrade leaders badly on on their gill plates; if the snook is over 20" it's basically a guaranteed re-tie, you might get 2 if they're 14-16". I tie uni to uni with braid or mono to fluoro and for nanofil to fluoro I use an alberto.
Snapper fisherman especially are picky about light hooks embedded in bait and using really light fluorocarbon leader.
Speaking of snapper fishing, today and the two preceding days, along with upcoming Friday, are the four days per year you can keep them in Atlantic Florida. Drove 3 hours Friday night. Woke up at 5:15 Sat morning, got to buddy's early, boat pre-loaded, everything perfectly smooth. Brisk offshore breeze. Ride out, about 18 miles, get to the spot, several other boats working the same ledgeline in close vicinity - within 80 yards in some cases. Wind and chop are pushing the boat. I feel like I'm okay jigging, but the bait guys are getting twisted and spun and don't think they're in the strike zone. We fish for about 20-30 minutes, I get a false albacore on the jig, probably 12#, great fight. They decide to try to anchor, so I go up front, fetch it out, and they're taking forever looking at the depth sounder and I've sat down on the deck. I start getting sick. I stand back up and stare into the wind at the horizon and settle a little. They still have their fists up their ass, I ask what is up, they tell me to put the anchor away.
Power steering leak in the console, no steering, no pressure in the system so the motors are free to wobble back in forth and won't track straight. The bow keeps catching the offshore wind and turning the boat towards Morocco. We get some outrigger line, lash the steering nut mount brackets to each other and the outboard stern cleats on each side, and this kind of holds them but there's still stretch in the line, the bow catches chop, and the boat veers off course. Basically have to ride in, two of us, one on each motor, outboard of the hull standing on the motor bracket, holding the motors straight so the slight play in the cord doesn't let the boat get off course, and when it does, we kind of wrestle against the cord to angle the motors a hair and turn back on course. At about 9 miles it gets a little better with the chop subsiding, and still a little better inside 5. We rummage and find some slightly stronger, less stretchy cord, re-rig, and thank heavens it was an offshore wind and incoming tide because Sebastian gets bad standing waves on top of each other over the rocky bottom on an outgoing tide and onshore wind. We get through the jetties, the bridge, and into the lagoon are able to limp down the ICW back to the dock, and kind of drift/pivot back into the slip.
Took like 5 hours to go 18 miles in a boat that can go 60, caught one fish.