I think I had one of the fastest processed passport renewals last year. Applied at about 9 am on December 23rd, passport arrived in the post at 8:30 am on Dec 24.
You can do it online and itās relatively straightforward but you need to have the public services card, a mygovid, proof of address and proof of residency (if not born here).
If you donāt have one of the above, you have to go into the office and fill in the paper forms. My other half had a torturous time getting his because he became an Irish citizen in be the late 80ās, I think, and the citizenship certificates from back then are much different to the current ones and they wanted it for proof of residency, even though he also has an Irish passport. The driving licence office people hadnāt seen one like it and there was a big rigmarole sending the forms off to HQ etc. etc. It took ages. I think it was his fourth licence, so heād been driving for 30 years and never had a problem renewing the old style ones.