At that time, taking SIM card meant free life. We used to recharge only to call. The income call was free. But now, telecom companies have changed their route.

If you keep the sim separate for a few months, companies deactivate the SIM. Therefore, you have to recharge with a plan. But do you know the argument behind the 28 -day validity?

For example, suppose you recharge with a 28 -day validity plan every month. You have to recharge 13 times a year. You are recharging for 13 months.

So many people prefer plans with annual validity. But they cost more. Compared to 28 days validity, the 365 -day plan benefits the user. Therefore their validity is kept 28 days.