When you work, you pay PRSI contributions.
When you sign for jobseekers, you are given a PRSI contribution credit.
PRSI contributions (paid or credited) will be counted towards your pension (only one contribution per week can be counted, so it will either be the paid contribution or the credit).
It might have been suggested that you switch from jobseeker's allowance to FIS (family income supplement) because you would be entitled to more money on FIS. If you qualify for FIS, it is paid each week and reviewed once each year. You would not have to sign on each month if you are on FIS. You must work a minimum of 19 hours per week to be eligible for FIS - if your work hours go below 19 regularly, you might not qualify.