St. Croix tells you in their warranty what they will fix at their expense (plus your $25 or whatever it is return fee), and what you'll be expected to pay them to fix. The warranty text came with your rod, and is available for their current models on their website.
I had a LU break while fishing, and they replaced the tip section quickly - though I must say the repaired tip section was less than aesthetically pleasing and looked like a 2 year old did the gluing on the thread wraps. A quick note to them and it was as good, or better than, new.