You need to recharge your prepaid number at least twice a month to enjoy uninterrupted services if you are a cell phone service subscriber and are a prepaid mobile user.
If worse came to worse and not an item of daily use certainly, in the past, phone cards were treated as an emergency item that you could use to keep connected.
Personal calling cards, which in decades past have gone out of fashion, are also making a comeback for sure, possibly because of the popularity of business cards.