I think it's daily.
Isn't he talking about the sMerit given to merit sources?
The source sMerit will come back in 30 days after its spending date. If you sent 5 source sMerit on 18 March, you should receive 5 source sMerit again on 18 April. So if you spent it daily during the previous month then you'll receive it every day in the next month.