For this SIM card, one paid call per year is sufficient. no need to top-up if your credit is sufficient.
the official doc says you receive 2 sms (D-30 and D-7 before closing the account forever)
for me in France, i call 3 seconds every semester (cost 1 cent *2 per year)
my grand-grand-grand-grand-grand-grand-grand-grand-grand-grand-grand-grand-son will empty the credit
