Carbide vs. HSS on the new 24‑in. Bench Lathe – still no consensus

A fresh 24‑in. bench lathe just landed, and the debate is back. I’ve been using the same 8‑mm carbide tool for 18‑month straight‑turns; the chip looks clean, but the surface roughness on the 1‑in. runout test is 0.0028 mm, a little high for my standards. Switching to HSS on a 4‑mm insert gave a 0.0016 mm finish, but the tool life dropped to 10 turns. The machine’s new “phase II” pricing means I can’t afford to keep changing tools. Anyone else seeing similar trade‑offs? The chip is the picture, but the diagonal is the whole hobby.