This is exactly the kind of small, everyday decision where "just grab one" quietly costs you money — because you make it 365 times a year. Mio doesn't care about vibes — here's the math.
A konbini coffee (7-Eleven, FamilyMart, Lawson) is typically ¥100–180 for a real drip cup, and honestly good. A café — Starbucks, Doutor, Tully's — runs about ¥350–550 for a small drip or latte. Brewing at home, drip or instant, works out to roughly ¥20–40 per cup once you average out the beans (illustrative — depends on what you buy).
| Where | Per cup | × 365 days |
|---|---|---|
| Home (drip/instant) | ~¥30 | ≈ ¥10,000/yr |
| Konbini | ~¥120 | ≈ ¥45,000/yr |
| Café (Starbucks/Doutor) | ~¥410 | ≈ ¥150,000/yr |
The gap is the whole story. Switching a daily café habit to konbini saves roughly ¥100,000 a year. Switching it to home brewing saves about ¥140,000 a year — real money, from one small decision repeated.
Here's the nuance Mio won't pretend away: at a café you're not paying ¥410 for coffee you could get for ¥120 at the konbini. You're paying for a chair, wifi, air conditioning, a table, and a place to sit for an hour. That's the real product. If you'd otherwise rent a co-working desk or just need somewhere to work, ¥410 for a seat is a fair price — the coffee is a rounding error.
So the honest question isn't "café vs konbini." It's: am I buying coffee, or am I buying a workspace? If it's coffee, the konbini already won. If it's the seat, pay for the seat and stop feeling guilty about it.
On paper, home is the runaway winner at ~¥10,000/year. The catch is behavioral: home only wins if you'll actually make it. A dusty drip machine and a bag of stale beans save nothing. If you know yourself and won't brew before leaving the house, the realistic contest is konbini vs café — and konbini wins that on cost every time.
Buying coffee → konbini. The ¥100 cup already killed the case for a daily café on pure cost. Will actually brew → home, and pocket ~¥140,000 a year. Buying a workspace → café is fine — just know that's what you're paying for. The "right" answer isn't about taste — it's about what you're really buying.