Engineering leveling guide: 1 to 300 for the least gold

How this is computed

At each skill point the recipe with the lowest expected cost per point is taken among the orange and yellow ones: orange recipes always skill up, yellow ones with a chance that shrinks as they turn green. Green recipes need several crafts per point and are skipped unless nothing else can still skill up. The times a step is crafted is the expected count, rounded up.

Reagent prices are the lowest listing in the latest auction house scan of your faction, then the price a vendor charged when our recorder met one, then the client's price for the reagents Classic vendors always stock. A reagent nobody sells but a recipe makes is crafted when that is cheaper. Reagents with no price are marked and the step's cost is a floor.

Only recipes taught by trainers are used (no drops or rare patterns). Skill requirements not read from a trainer are estimated from the recipe's colour thresholds and can be off by a few points.

Training is added: each recipe at the price a captured trainer charges (≈ when estimated from the captured price curve — the client has no trainer prices) and the rank tiers at 50, 125 and 200 (5s, 50s, 5g, as read off trainers).