If you're coming to Ireland you might have to think about how you're going to change your dollars into euros. Now, I can't magically make the weak dollar strong or the high prices here low, so be prepared to find everything expensive.
Still you can save some money by avoiding going into banks to change money. Use your bank/debit card at the ATM's. I carried out a small test in mid May. I changed a chunk of money in the bank and the same day I withdrew some from the ATM using an American debit card. Well, the Ulster Bank charged me $1.3943 for each €1. (And, no, the experience would be no different at any other bank, but I would have had to pay another handling charge at any other bank because I'm not a customer there.)
Using my MasterCard debit card (the American bank's ATM card) the rate was $1.3665 per €1. The American bank also charges $1 per transaction, but there is no charge from the Irish banks when you use their ATM's. If I had changed $400, for example, I would have saved around $5 -and that includes the ATM charge from the American bank, but not any potential charge from the Irish bank if you go inside to a teller (and there will be a charge.)
Most ATM cards have a daily limit of somewhere around $500 and you might even find that you can only withdraw €300 in any one transaction here. So, if you need to change big amounts in one go you could be stuck with a bank transaction. (And, if you can, use your credit card. That's also cheaper than changing money in the bank, but the lack of a chip on the American cards can be an issue.)
Anyway, what I'm saying is that if you need spending money in Ireland, use your ATM. Just be sure your card is part of either the Cirrus or PLUS networks before you leave home. Those two networks are available at most ATM's here. You can safely forget about the old traveler's checks.