For current patrons who plan to stay at the same tier, nothing will change for you. This mostly applies to new patrons, or patrons that change pledge tiers during the month.
Some further information from Patreon regarding this feature:
How will this feature change how patrons are charged?
New Patrons: New Patrons will be charged on the day they become your patron, giving them access to all content shared with their reward tier. On the 1st of the following month, they will simply return to being charged monthly at the beginning of the month.
After the initial immediate charge, all following charges will take place on the 1st of each month. If someone becomes a patron to a creator towards the end of the month, this might come across as a double charge; but the initial charge acts as payment for the month in which they became a patron and the next payment is for the month following.
Existing Patrons: Your existing patrons will be charged on the 1st of the month like usual.
If an existing patron increases their pledge, they will be charged the difference between their last pledge value, and the new pledge value. On the 1st of the month (and every 1st of the month thereafter) they will be charged the full amount of their pledge until they cancel or edit their pledge.
If an existing patron decreases their pledge to a creator who is charging up front, they are not charged right away when they lower their pledge amount. The new pledge amount will be reflected when their pledge renews at the beginning of the next month.
Hopefully this will help with keeping events running smoothly for you guys <3