Two different reasons rent is late
The first is forgetting. Rent is due on the first, the first is a Saturday, and the transfer does not happen until Tuesday. This is the problem a reminder actually solves, and it is common enough to be worth five dollars.
The second is not having the money. No reminder changes that, and sending more of them mostly damages a relationship you will need if you want a payment plan to work.
Being honest about which one you are dealing with saves a lot of wasted effort. If most of your late payments arrive within a few days, you have a forgetting problem. If they arrive weeks late or not at all, you do not.
When to send it
Two or three days before the due date is the useful window. Far enough ahead that a tenant can move money, close enough that they will not forget again before the date arrives.
Sending on the due date itself is too late to change anything. Sending a week ahead gets forgotten. The gap between those two is where the reminder does its work.
A working example: MAPLE COURT: rent is due Friday the 1st. Thank you to everyone who pays on time.
Wording that does not sound like a threat
A reminder should read like a courtesy, because that is what it is. Stating the date and thanking people is enough. Adding a warning about late fees turns a helpful nudge into something tenants resent, and it goes to every tenant including the ones who have never been late.
That last point is the one landlords miss. A broadcast reaches everybody, so a sharply worded reminder punishes twenty reliable tenants to reach the two who are not.
Keep the tone flat and the message short. The tenants who needed reminding will act on it, and the ones who did not will barely notice it.
What to do about rent that is already late
Handle it individually, not in a broadcast. A message to the whole building about late rent is both ineffective and unpleasant for everyone who paid.
Late fees, demand letters and anything leading toward eviction are governed by your state's rules on notice and timing. Those need to be in writing, served the way your state requires, and are worth confirming with a local attorney rather than improvising.
A broadcast has no record of who owes what and no way to say anything to one tenant that it does not say to all of them. Building notices and maintenance messages is where this tool is genuinely well suited.
Where it fits against payment systems
Online rent platforms handle reminders as part of a wider service, along with tracking payments, applying late fees and keeping records. If you want the reminder tied to whether a tenant actually paid, that is what you need.
The trade is a monthly cost and, on many platforms, a transaction fee. For a landlord with a handful of units who simply wants a nudge going out each month, that can be more than the problem is worth.
Five dollars once for a list of 100 tenants sits at the other end of that scale. It is a reminder and nothing more, which is either exactly right or clearly insufficient depending on your situation. Comparing per-send against subscription costs covers the maths.