In theory for the rate of tax to be kept the same everything needs to rise with wage inflation.
Tax credits go up 4.5%. Entry point into 40% income tax goes up 4.5%. Amount of transferable benefit between spouses goes up 4.5%, USC band etc etc.
Some countries do this automatically. It’s not a tax cut. It’s just standing still. In Ireland it’s positioned as a tax cut ‘giveaway’.
The annualised ‘cost’ of doing so is €1.2bn. Or more accurately, if not done the government is increasing the rate of taxation to the tune of €1.2bn.