Thanks. Been using Mac for years. I use Calendar for every reminder I need such as Pay Bill, Appointments, To Dos, Holidays, Birthdays/Anniversaries, even Phillies and Eagles football schedule. Color coding each category gives me instant visual feed-back when looking at the Calendar in weekly or monthly view.
One of the coolest features is when I receive an email about a bill coming due, etc. all I have to due is click on the date and I'm able to set an event that goes straight to the Calendar.
I like the flexibility of moving an event from one day to another when necessary. Checking past events. Flexibility in noting the exact time and day I want to be reminded. Setting recurring events.
I just never got why Reminders was necessary. It just seemed somewhat redundant although it lacked some of the features of Calendar.
Again, thanks for your explanation. It helped me understand these 2 features of Mac OS.