My wife keeps reminders for every registration date, and we still forget some. A calendar helps, but it only works if we can actually see and use it.
Give each event more than one date
Record registration opening, the event itself and the last day to cancel without losing a fee, if the organizer offers that option. Add any travel cancellation deadlines separately. These dates answer different questions.
Save what you will need at opening time
Keep the official registration link, the correct division and required membership information handy. Check which time zone the opening time uses. An alert at the wrong time is an easy mistake.
Check in together
A brief family check-in can catch schedule conflicts before money is committed. Include school, work and the things your family enjoys outside golf.
Make a backup plan
If registration closes or a waitlist does not clear, consider a local round or practice visit. A calendar should support your family, not turn every empty weekend into an obligation.