A torch, a SIM ejector pin and ten minutes. Where the liquid indicator sits on iPhone and on Android phones, what corrosion looks like at the ports, the speaker and mic tests that expose it, and why a phone that works today can still fail next month.
A lost phone can be blocked on every Indian network for free, through the government CEIR portal. Here is the exact process, the documents you need, and how to unblock it if the phone comes back.
The window in which a problem is easy to prove is short. This is the routine that protects you, in the order that matters — IMEI first, then ownership, then the numbers you were promised.
A replaced screen is not a problem. An undisclosed one is — it changes brightness, touch, water resistance and resale value. Two minutes of checks, no tools needed.
The one number that decides whether a used phone is a bargain or a daily annoyance — how to read it yourself where the phone supports it, where the real cut-offs are, and the three ways it gets faked.
Thirty seconds, free, and it is the only check that can save you the whole phone. How to read an IMEI off a handset and verify it against the Government CEIR database.