There are credits and there are contributions:
You pay contributions when you work.
You get credits while being on SW payments under certain conditions.
You need 520 paid contributions to get a minimum pension payment.
If you have those 520 paid contributions you can use your credits as well to boost your pension. At the moment you can use all your credits- theoretically 30 years on top of your 520 paid contributions to get a full pension.
There will be a cap on the credits you can use- it will be only 520 SW credits within 11 years time. A lot of changes coming in now.
Everything is explained here- and not too hard to understand:
The State Pension (Contributory), previously called the Old Age (Contributory) Pension, is payable to people aged 66 and over who have worked and paid enough social insurance contributions.
www.citizensinformation.ie
www.gov.ie