Jobseekers Benefit which is payable for a max of 9 months is an entitlement based on your PRSI record. If you give up work within the 9 months it will revert to the full rate. The benefit is based on the number of days worked, not how much you earn. But in claiming JB you are expected to be actively seeking full-time employment.
After the 9 months you can claim Jobseekers Allowance, but this is means tested. Again you are expected to be actively seeking employment and the local SW office will expect you to produce evidence of what you are doing to seek employment.