Consumption Smoothing
Match your spending to your lifetime income curve, not just today's balance
Consumption smoothing is the economic principle that your goal is not to maximise saving at all times, but to keep your standard of living roughly stable across the full arc of your life. Your income is volatile — you earn little when young and studying, earn more in mid-career, may dip when children arrive and you have less time, then recover in late career as costs fall and mortgage is paid off. Trying to match your spending to your income at every point produces a bumpy, volatile life. Smoothing it out is the economically rational goal.
The counterintuitive implication: borrowing when young and income is low but future earnings are confident is not just acceptable — it is rational. A student who expects to become a well-paid professional has good reason to take on debt now and repay it later when income is higher. Equally, the person with young children who is barely saving is not necessarily making an error — mid-life is often the peak cost period and the nadir of saving capacity.
Angner arrived at this framework partly from personal experience: he completed two PhDs, exiting school in his mid-30s with no savings, and only began serious saving in his 40s. He notes this is not ideal but not catastrophic — even late starters can accumulate meaningful cushions, and 'even relatively small amounts act like an airbag if something goes wrong.'
- The goal of lifetime financial planning is stable consumption, not maximising saving at every point.
- Borrowing when young and income-constrained but future earnings are confident is economically rational.
- Mid-life (children, peak costs) is the expected trough of saving capacity — not evidence of failure.
- Even starting late, small amounts compound meaningfully over a ten to twenty year window.
- The right debt is investment-oriented (education, a car that expands earning capacity) — not consumption debt.
- Map your expected lifetime income curveRoughly sketch when your income will be low, rising, peak, and declining. Students, early-career, peak-career, and retirement each have different income profiles. This map tells you where you are on the curve.Pro tipYou don't need precision — a rough sketch of three or four life phases is enough to make meaningfully better decisions than treating every year identically.
- Identify your current phase and its rational saving rateResearch cited in the episode shows optimal saving rates are non-linear: high in early adulthood before dependents, near zero during peak child-rearing costs, then sharply higher (25%+) once children leave. Adjust expectations for your phase.Pro tipIf you're in your 40s with young children and barely saving, you may be doing exactly what the economic model predicts — not failing.WarningDo not compare your saving rate to someone in a different life stage. The comparison is meaningless without accounting for phase.
- Evaluate borrowing decisions against future earning confidenceGoing into debt is rational if: (a) it funds something that increases future earnings (education, transport to a better job), and (b) you have a reasonable basis to expect higher future income. It is irrational for pure consumption (luxury goods, holidays funded by credit).Pro tipAngner's rule: is this borrowing an investment in future earning capacity? If yes, it may be rational. If it's a handbag, it is not.WarningConfidence in future earnings must be evidence-based, not wishful thinking.
- Start saving as soon as the phase allows — not when it feels perfectAngner did not start saving until his 40s. He is clear this is not ideal — earlier is better — but 'that doesn't mean it's not doable.' Even small amounts in a long window compound. Do not let the ideal timing be the enemy of starting now.Pro tipA small cushion acts as an airbag for unexpected expenses (dental work, job loss) regardless of how late you start. The first goal is not retirement wealth — it is the emergency buffer.
- Resist over-saving as much as under-savingAngner notes explicitly that you can save too much. Saving at 90% of income in your 30s while deferring all life enjoyment is not economically optimal — it front-loads sacrifice and back-loads consumption in a way that mismatches to the lifecycle.WarningOver-saving for its own sake is a form of present-bias in reverse — sacrificing current wellbeing for a future that may not arrive as planned.
Angner completed two PhDs, remaining in graduate school for ten years. He was in his mid-30s before entering the job market as a philosopher, with no savings. He only started serious saving in his 40s.
Research cited in the episode shows the optimal saving path is non-linear. Early 20s (no dependents, low costs): save high. With young children: save near zero. When children leave: ramp to 25%+. This path smooths consumption across life stages.
Angner notes that economists often say students should take out larger loans if they expect high earnings post-graduation. This allows them to smooth consumption across the low-income student years.
Consumption smoothing is a classic result in lifecycle macroeconomics, developed formally by Franco Modigliani (Nobel laureate) in the 1950s as the 'Life Cycle Hypothesis.' Angner brings it into personal finance by connecting it to his own financial trajectory (two PhDs, late start) and the practical reality that people feel guilty about not saving during high-cost life phases when in fact the economic model endorses reduced saving at those stages.