Engineer Lean FIRE: Freedom at Any Income
FIRE Number
$750K
Target Retirement Age
46
Years to FIRE
18
Monthly Savings Needed
$2K
Non-software engineers — mechanical, civil, electrical, chemical — earning $90,000–$130,000 are well-positioned for Lean FIRE at 45–50. On $110,000 income saving $2,000/month (22% savings rate), the $750,000 Lean FIRE target is reached in about 18 years from age 28 — age 46. Unlike tech-level salaries requiring extreme frugality to reach Fat FIRE, the engineer's income makes Lean FIRE achievable at a moderate savings rate without significant lifestyle sacrifice.
Defense contractor and utility engineers often have defined benefit pensions alongside strong 401k matches — a Lean FIRE accelerant that many peers in tech lack. An engineer with a pension providing $25,000–$35,000/year at 52 only needs $0–$200,000 in personal savings to meet a $30,000/year Lean FIRE budget. In this case, Lean FIRE is effectively achieved through pension alone, with personal savings providing additional security.
Geographic flexibility matters for engineers choosing Lean FIRE. Engineering firms in LCOL cities (Huntsville AL, Knoxville TN, Oklahoma City OK) offer $90,000–$110,000 salaries with costs of living 40–60% below major metros. An engineer earning $100,000 in Huntsville keeps more after-tax income (no state income tax in Alabama... Tennessee has none on wages), needs a smaller FIRE number due to lower local costs, and can accumulate $750K in 15 years on a 30% savings rate.