>>680734>should i or should i not run a leader?Depends on the water I guess. I never run a leader using 20# braid and I still catch plenty of bass and sunfish with it. I caught pic related (7lb 12oz LMB) last year using a texas rigged soft plastic crawdad tied directly to braid.
>and if i do run a leader, what test should it be? and how long?Depends on what you plan on catching and where you'll be fishing. For bass I'd run like an 8#-10# leader that's 4ft-8ft long.
You definitely don't NEED a leader, you can try fishing for a while without one and then put one on at a later date to test it out. If you notice a dramatic difference in the amount of bites you're getting then you can start using a leader full time then.