You waited. That's fine — most Americans don't start until 28 or later. At 30, your compounding runway is 35 years, and the 2026 limits give you serious room.
Week 1. Enroll in your employer's plan and set your deferral rate to at least the match ceiling. At a 5% match on $70,000, that's $291 a month of free money.
Week 2. If you're in the 22% or 24% bracket, split 50/50 between Roth 401(k) and traditional 401(k). You genuinely can't predict future tax rates; splitting is a hedge, not indecision.
Week 3. Pick a target-date fund dated around 2060. Yes, those funds are boring. Boring wins here. Don't spend three weekends researching allocation.
Week 4. Open a Roth IRA at Fidelity or Schwab. Set up $625 a month to automatically invest in a total US index fund. You will hit the $7,500 cap.
At 30 with a $70k salary, contributing 5% to 401(k) + $7,500 to Roth IRA + 1% raise per year, you hit $1 million at 58. The tax savings calculator will walk through your exact bracket math.