I still write 'none' in any postcode fields, and am refusing to learn my eircode. I've never had a problem getting things delivered

May I ask why?

As an outsider (and someone who knows nothing about you/your culture) this sounds like "I don't want to accept change" or "noone is going to force stupid codes on to me". So id love to hear the reason!

Seconded. I'm also Irish and the new postcodes are the ultimate in clarity imo. Each dwelling/unit has one code, and each code represents one dwelling/unit.

I live in quite a remote spot, so before, my address was just my name + the general area I live. Thats fine for the postman who knows where I live, but I dont know how other delivery services figured out where I was. Also I'm pretty much at the centroid of 3 towns, and different services would route deliveries via different towns. I had to learn through trial and error to put 'via X' or 'via Y' as my address depending on what service I was using.

Eircode clears all that up.