That's not a technical question. It's a commercial decision of the provider what to offer. Just check all providers that sell prepaid sims (or prepaid phones) where you live and choose the one that fits you best.
Since the packages vary both between countries and in time, there's no universal answer. That's why you can't find it.
For example, here (in the Netherlands) I'v seen prepaid packages of 10 euro which keep valid forever, provided you use it at least once in 4 months, even if that is a free call to 1244 to check the balance.
Moreover, it makes sense to have a sim-card that uses a different network than your regular provider. That way, your back-up phone works also when your regular phone doesn't work because of network issues.
I am looking for a cell phone plan whereby I can purchase a basic cell phone, add a block of minutes to it, and not have the plan expire, or have to keep putting minutes on the phone. I would like the minutes to just continue to be available as long as I have the phone.
The phone would be used as a back-up phone in emergency situations only should my primary phone be out of commission.
If this doesn't exist in the cell phone world, what is the best inexpensive option.
I have seen this question all over the Internet, however; there has been no viable response to the question.
Hoping to find it here.