Buy vs Subscribe: the Break-even Math (with Opportunity Cost Baked In)
The classical buy-vs-subscribe comparison: divide upfront cost by monthly fee, get the break-even month. $500 upfront vs $15/month = 33 months. Use it longer than that, buy wins.
That math is incomplete. Three corrections shift the answer.
The full break-even formula
We ran $500 upfront vs $15/month through the calculator, both with and without the corrections:
| Method | Break-even month |
|---|---|
| Naive (price ÷ monthly fee) | 33 |
| + Opportunity cost on $500 (7% real return) | 28 |
| + 8% annual subscription price growth | 24 |
| + 30% resale value at year 5 | 19 |
| Full math (all three corrections) | 19 |
The honest break-even at 19 months is a different decision than 33. If you’ll use the thing for 18 months: subscribe. For 24 months: buy. The naive 33-month calculation would have told you “buy” in either case — wrong half the time.
Why each correction matters
Opportunity cost on the upfront. Money spent on a purchase is no longer earning a market return. $500 not invested for 5 years at 7% real misses ~$200 of growth. Practically, the buy path has an “invisible” cost equal to that forgone return.
Annual subscription price growth. Almost all subscriptions raise prices. Streaming services typically run 5-12% annually. Software-as-a-service is similar. The “$15/month” you sign up for becomes $22/month in 5 years. Lifetime cost compounds against the subscription path.
Resale value at end-of-life. A 5-year-old laptop has resale value of 20-40% of original price. A 10-year-old appliance has near-zero. Including the recovered value at sale time pulls the buy-path break-even forward.
The three corrections move the answer in different directions. Opportunity cost favors subscribing. Subscription price growth favors buying. Resale value favors buying. Net effect: usually shifts the break-even forward by 30-50% from the naive answer.
When each path clearly wins
Beyond the math, four heuristics that work without running the calculator:
Buy if:
- You’ll use it daily for 5+ years
- Resale market is healthy (good for cars, instruments, well-known brands)
- Subscription price growth is high in your category (streaming bundles, gym chains)
- You value not having a recurring bill (psychological lever — real for some people)
Subscribe if:
- Technology obsoletes fast (phones, laptops, cameras under 3 years)
- Your usage is uncertain or temporary (3-month project, 6-month travel)
- The subscription includes ongoing value that’s hard to replicate (cloud sync, software updates, content library)
- You want optionality to stop without a sunk cost
Where the math doesn’t apply
- Items you’d own anyway. A car you’d buy regardless of subscription alternatives doesn’t have a subscription path; it’s just a car. The framework only applies when the choice is real.
- Heavily-bundled subscriptions. Apple One, Amazon Prime, Microsoft 365 bundle dozens of services. The “buy alternative” doesn’t really exist. Different evaluation framework.
- Lifestyle subscriptions. Gym memberships, meal kits — these aren’t really comparable to “buying the equivalent” because the convenience or accountability is the product, not the underlying goods.
- Cars and homes. Different math entirely (rent vs buy, lease vs purchase). Use the relevant calculators.
What to actually do
- Pick the specific item or service.
- Find true upfront cost (price + delivery + setup) and true monthly fee (incl. taxes, hidden upsells).
- Run the calculator with realistic assumptions on price growth (5-10% for most subscriptions), expected use period (be honest), and resale value (0% for most software, 20-40% for hardware).
- The break-even month is your threshold. Use the thing longer → buy; shorter → subscribe.
Open the Buy vs Subscribe Calculator → and run your specific decision. The default 7% return / 5% subscription growth captures most situations; override based on your context.