I am currently living abroad, in a country which 48 does not work in.

However, I intend to move back to Ireland in potentially 2-3 years and would like to retain the same phone number if possible as I have grown attached to it. How long can I go without purchasing 48 membership before my phone number gets disconnected?

If I top up my phone with a membership once a year, even if I don't use any of the data or send any texts, will that be enough to keep the phone number active? - I looked into porting my number to a virtual phone service such as Google Voice, but it seems to only be available to people in the US and I have not found a similar service that will accept Irish numbers