After university I tried to start a business. For the first four years (2016-2020) my income was too low (<€5k) to require any PRSI contributions. As I did not have enough prior credits (or, in fact, any) I could not make voluntary contributions during those years. I realise now that I should probably have gotten a part time job to ensure that I did get credits, but I unfortunately didn't think of it at the time. I am pretty sure that nothing can be done about it now, but as I regret the loss of those four years of credits quite a bit, I thought I would ask here just to be absolutely sure.