A huge part of what makes ADHD a disorder is the fact that it's incredibly difficult to form and retain habits (aka executive dysfunction). Alarms, reminders, etc. might increase the likelihood that any given task gets done, but not by much, and it doesn't guarantee that task will get done with any regularity whatsoever. The other part of executive dysfunction is difficulty with task initiation. I can't speak for every ADHD'er but, if I manage to remember something needs done, there's a solid chance I simply wont be able to get it started. I'll sit on the couch for literal hours, knowing that I need to do the laundry, that if I don't do the laundry I won't have clothes to wear tomorrow, that it'll take me 5 minutes to get the load started, that I would be so much better off if I just did them, that I would feel good having accomplished just one thing today, on and on. But my body physically won't move. Ill be sat still, staring blankly at a wall for hours, screaming at myself to just do SOMETHING, and yet I can't will myself to move.

You saying "just set a reminder" is akin to telling a depressed person to just not be depressed. Like, gee thanks! I didn't know you can just do things. Guess I don't have "can't just do things disorder" after all!