まいつき毎月maitsukiまいげつ毎月maigetsu
1.
A term that signifies occurring on a monthly basis, indicating that an event takes place once every month without exception.
2.
Referring to the consistent repetition of an action or event in every individual month throughout the year.
3.
Describes a frequency that applies uniformly to all months, highlighting the regularity of occurrences periodically within a monthly timeframe.
Example:
私は両親には必ず毎月手紙を書きます。