Handling 1st vs Last Day of Month for Targets?

Final question for today: How do folks handle assigning dates for budgets when something doesn’t have a discrete date, like a mortgage?

For things like shopping or groceries that happen across the month at uneven intervals, do folks budget for the first day (saying “I want to have all the money I need for the month the day the month starts”) or the last day?

Would love to hear how others approach this as I wrap my head around YNAB’s system.

Thanks again!