Have you paid PRSI contributions in the past?
If so, it is worth your while signing on for the following reasons:
1. You preserve your pension entitlements by getting a PRSI credit each week
2. You preserve your short-term benefit entitlements with these credits. Illness Benefit (which is not means tested), Jobseeker's Benefits (should you requalify by working for three months), Dental, Optical, etc.
3. If you decided to go back to education, you need to be signing on to apply for BTEA.
4. You could apply for Back To work Allowance as an employee or self-employed in the future and you'd need to be claiming SW to get that.
There are many stories of people who didn't claim benefits as they thought they would only be out of work for a few weeks adn found themselves still in the same position months later, regretting not claiming.