Where the data goes

The bundle was two gigabytes on Monday, fat and confident. By Thursday the phone says data exhausted, and you are genuinely confused — you watched nothing, or so your memory insists. The memory is honest; the bundle was still eaten. A bundle is a bowl of water in a house with four quiet drinkers, and this lesson is about learning their names, because a drinker with a name can be leashed.

The eaters, by appetite. The updater: every app on the phone checks for new versions, and the big ones — the social apps, the maps — update in the hundreds of megabytes, over your bundle if you let them. The leash is one switch: updates over Wi-Fi only, the updates lesson's law, and the biggest eater sits down. The backup: photographs climb to the cloud all day on mobile data if the gallery's setting says so — fifteen years of family history quietly metered. Backups belong to Wi-Fi, or to the nights when you switch them on yourself. The streamer: video drinks data the way the noon sun drinks a bucket — an hour of high-quality video can finish a daily bundle alone; the caption lesson's settings hold the cure, because a lower quality looks the same on a six-inch screen and drinks a tenth. And the background: apps you are not even using, refreshing feeds, syncing, checking — the settings page has a screen that names every eater on the phone and shows exactly how much each drank this month. Open it once, with the confusion of Thursday in your mind, and the mystery dies in ninety seconds of honest reading.

The leash, and the buying

Three switches leash the house for good. Data saver, in the network settings — the phone stops the background drinking and lets the foreground apps eat only when you are actually looking. Auto-update over Wi-Fi only, as above. And a data warning set at three-quarters of the bundle — the phone taps you on the shoulder before the exhaustion, not after, which turns Thursday's surprise into Wednesday's decision. Then the buying itself, briefly and firmly: bundles come from the network's own app, its own portal, its own codes — never from the market agent who promises a bigger bundle for less, because the oversized cheap bundle is the recharge-card scam of this decade; the SIM either works at half speed, or works at all until Monday. Know your cycle — the day it renews, the day it dies — and note it in the weekly book beside the airtime. A bundle with a known birthday cannot ambush you.

And the dual-SIM clause, because half the phones in this country carry two lines: data comes out of exactly one SIM — the one the settings call the data SIM — and the switch that chooses it lives in the network settings. The classic tragedy is the data on line one, the browsing on line two's airtime, discovered at month's end in the balance. Check the switch once, after any software update, and whenever a bundle refuses to work: the phone is usually obedient; it was only never told. Bundle, leash, switch — three words that turn the bowl from a mystery into a managed meal. The next lesson walks to the machine that eats a different kind of money: the cash machine at the bank, and its market cousin.

• Open the data usage screen today and read the list by mouth size. The mystery dies in ninety seconds.
• Three switches: data saver on, updates over Wi-Fi only, gallery backup on Wi-Fi only.
• Set the data warning at three-quarters. Thursday's surprise becomes Wednesday's decision.
• Bundles from the network's own channels only. The oversized cheap bundle is a costume with a zipper.

The managed meal

Two gigabytes is not a small bundle; it is an unmanaged one. Named eaters, three switches, a known renewal day — and the same two gigabytes stretch to the end of the month with room for the videos you actually chose to watch. Data is money in a different costume, and it obeys the same law this shelf has taught since lesson six: what you do not watch leaks. Watch the bowl. The next lesson goes to the bank's wall, where the money becomes notes — and where a new generation of thieves waits at the slot.