You can set reminders for every day etc.
Just say, "Alexa, remind me to go to the gym", she says, when should I remind you, you say "Every day at 1430", she says OK, I'll remind you to go the gym every day at 1430.
I use this for feeding the puppies I have. It works for me doing it this way. Once I have the puppies on less feeds, I will change the routine and just tell her to cancel all reminders and set a new one.