Comment by adastra22

To expand:

If you put non-date-specific TODOs in your calendar, then as soon as the number of TODOs in that system becomes overwhelming, you stop looking at your calendar and start missing appointments & truly date specific reminders.

If you put date-dependent TODOs in your task tracking system, then every time you look at it you see a bunch of stuff you can't move on and you quickly lose effectiveness.

If something is dependent on a specific date or time, either because it is an appointment or because it is nonactionable until then, put it in a calendar or tickler file. If not, keep it the hell away from your calendar and put it on a TODO list (plain text file is fine). This keeps both systems effective.