I went through the same thing with my old trailer with Dexter 3500 lbs axles. The supplied leafs were basically $29.95 China junk. I had a spring shop build me some beef-cake springs that will never break. Cost me about $95 per spring. Raised the trailer about an inch. While you're at it, you should replace all hardware, like HD Shackle Links, HD Equalizer and put wet bolts with the zerk fittings in. Make sure you go with new U-Bolts too as they are not supposed to be re-used. I would also recommend bronze bushings in the leaf springs to replace the plastic junk bushings that wear out in about a year. They go nice with the wet bolts with the zerks.
I did all the work myself.
