How long will my number stay active if I don't use it?

[Guy20]

I have a pay as you go sim and I'm currently living abroad for 9 months. How long will the number stay active if I don't use it?

Also, do I need to keep topping up every month for it to stay active?

[Chris_B]

@Guy20  You need to make a chargeable call/text at least every 3 months to keep the sim active.  Topping up your account doesn’t do this.