Local LLM Rig Cost Payback: How Long Until It Pays for Itself?
A local LLM rig cost payback runs from about 4.8 months to infinity, and the machine is not what decides it. The same $3,500 RTX 5090 box pays back in ~4.8 months at 20 h/day against a $2/M API tier, stretches to ~39 months at 24/7 against a $0.50/M hosted open-weight model, and never pays back at all at 12 h/day — because a $133/month API bill undercuts a $137/month local rig. Payback is a property of your queue depth, not your GPU. ...