I've never used braided line, and I want to this spring. I know a lot of people use a fluorocarbon leader, but do you need to? Also I usually use a 12 pound fluorocarbon line. What does that relate to in braided poundage ( like the ratio of line thickness to pound test in braid)?

A key advantage of braid over other lines is it's strength to diameter ratio.  I find it ridiculous to choose a braid that is as large a diameter as the mono you are now using.  If you are happy with the strength of 12lb test mono now, choose a 15lb test braid or even a 20lb braid... diameter is a considerable factor in visibility and the thinner diameter braid may well be less visible than the same test rated mono or flouro.

I use a fluoro leader in clear water, slow presentations (jigs, tx rigs) where fish *might* see the lie, and occasionally when I'm having trouble with the limp braid fouling teh front treble hook.  Other than that, no.

Use a leader in clear water, or if you're fishing a lot of rocks. I use 50, 65, and 80lb braid. The 50/65 I use a leader with both of them on rocks or clear water. The 80 is for punching which I never use a leader for.

A key advantage of braid over other lines is it's strength to diameter ratio. I find it ridiculous to choose a braid that is as large a diameter as the mono you are now using. If you are happy with the strength of 12lb test mono now, choose a 15lb test braid or even a 20lb braid... diameter is a considerable factor in visibility and the thinner diameter braid may well be less visible than the same test rated mono or flouro.

15lb/20lb braid digs into itself when snagged or fighting a fish. For a spinning reel, 15lb is great. But if you're using a leader and/or fishing in heavier cover, 50 and 65lb braid is the way to go.

   Braid is VERY limp, it's a big reason why guys like it so much. Even 65lb braid is limper then 8lb fluorocarbon. Gives you a lot of power, yet still very manageable.

50lb braid I use anywhere from a 10-15lb leader if I'm using one. 65lb braid I use a 20-30lb leader.

No you don't have to use a leader. Those of us that do, will usually use a fluro leader most of the time.

I use 55lb Diawa Samuri braid, has the same dia. as 10lb mono..but I normally tie a 12lb fluro leader on it..depending on conditions, it's usaually 3 to 6 feet long. BTW, rocks and braid don't mix..so in rocky areas, use fluro, mono, or a copolymer.

I use a leader in clear water with slow baits because I got a good butt waxin' one day by people I normally beat.  They were using mono and I was using braid with no leader.

The only time I use a leader with braid is if I am fishing a slow bait in really clear water. If I am using a reaction bait I find it doesnt matter.

If the water is SUPER clear like the stuff in the FL Keys, use a leader. If the water has some stain, like most of my local waters, it usually won't matter.

By the way (just because I love to start trouble)...flourocarbon is no more invisible underwater than mono. Anyone who wants proof can email the editors of Sportfishing magazine and ask for a copy of their fishing line visibility test issue from a couple years ago.

No. 

i use yo zuri for all application except frogging and punching

for punchin and top waters

i use 70 lbs diawa samurai braid with out leader

I never use a leader.

If your in clear water yes definantly use a leader. But muddy water it really doesn't matter.

I have used braid for years sight fishing for spawning bass in East Texas. I never used a leader. I hammered them. I guess it depends on if the lake is always clear and what species you are after. I havent noticed a difference.