Lá is regular when it comes to counting. Irregulars are: bliain, seachtain, uair, ceann, cloigeann, orlach, pingin, troigh, slat, trian, ubh - and or course your namesake scilling :)

Samplaí ná dhá bhliain, trí bliana (déag); ceithre horlaí (déag); cúig seachtaine (déag); sé troithe, seacht dtroithe (déag); ocht slata, naoi slata (déag).

Regular examples: dhá lá dhéag, trí mhí dhéag; seacht n-earra dhéag; naoi n-artaire dhéag srl