The 30-to-90-Day Expense Baseline
Track every expense long enough to replace guesses with a usable baseline
- Difficulty
- Easy
- Time to result
- ~months to results
- Steps
- 5
- Confidence
- 96%
The baseline starts with observation rather than an immediate austerity target. Choose a tracking period of 30, 60, or 90 days and record every transaction, including small delivery, ride, and subscription charges that are easily forgotten when paid by card. Group transactions into categories, total them, and compare the result with what you believed you spent. Humphrey Yang describes discovering that his own monthly spending was $2,800 rather than the $1,500 he expected. The discrepancy is the useful output: it establishes the gap between income and actual spending and shows which behaviors drive it. A longer window captures recurring bills and smooths unusual weeks. Use the measured baseline to set a credible saving, investing, or debt-repayment target rather than building a plan on memory.
Origin
Extracted from The Diary of a CEO
Core principles
- 01A plan needs an observed starting point
- 02Small card purchases are easy to forget
- 03One month can expose large estimation errors
- 04A longer window reduces the effect of unusual weeks
How to run it
- 1
Choose the observation window
Commit to tracking for at least 30 days, extending to 60 or 90 when spending varies. Define start and end dates before reviewing behavior.
Pro tip Include at least one full cycle of monthly bills.
Watch out A short, unusually cheap week can create a misleading baseline.
- 2
Capture every transaction
Record card, bank, cash, subscription, and automatic payments. Do not omit small purchases because they feel insignificant.
Pro tip Export account transactions and add cash spending manually.
- 3
Classify and total
Group spending into categories that support decisions, then calculate the monthly total and category shares. Keep essential and discretionary costs distinguishable.
Watch out Do not make categories so detailed that tracking becomes impossible to sustain.
- 4
Compare belief with reality
Write down your pre-audit estimate and compare it with the measured total. Investigate the largest differences without hiding inconvenient items.
Pro tip Treat surprise as information, not as a moral failure.
- 5
Set one evidence-based change
Use the baseline to choose a specific saving, earning, or repayment action. Repeat the measurement to check whether the change altered cash flow.
Pro tip Start with a recurring cost or behavior visible in the data.
In the wild
Humphrey Yang says he tracked expenses for a month in 2014. He expected to find about $1,500 of spending but measured $2,800, revealing that his mental estimate was far below his actual outflow.
→ The audit gave him a real starting point instead of an inaccurate estimate.
Common mistakes
Relying on memory
Frictionless card payments make small purchases easy to forget, so recollection can materially understate spending.
Quitting before a full cycle
Stopping before recurring bills arrive produces an incomplete picture and weakens the plan built from it.
Is it for you?
Best for
It is best for people who avoid their accounts or cannot explain where their income goes.
Not ideal for
It is not ideal as the only response to missed essential payments or unmanageable debt requiring professional help.
From the transcript
“Track your expenses for 30 days, 60 days, or 90 days.”
“I thought I was spending 1,500 bucks a month. Guess what? I was spending $2,800.”
From the episode
No.1 Money Saving Experts: Do Not Buy A House! Putting Money In A Bank Makes You Poorer!