You can create and schedule your messages hours, days, and months in advance. No need to set reminders. Create your message while it's on your mind.
If scheduling to a List, your scheduled message will send to everyone in the List at the time of sending. For example, if you schedule out a message to your List of 150 people, but before the message sends you have 10 new people join your List; the message will send to all 160 people.
To schedule a message just choose send later when creating your message.