You are right.
For me, personally, I think it would suffice to just see that my daily report for Monday has not been done, hence most likely not done for the following days either. If I have been ill, I probably have a backlog in many areas. I would set up whatever lists or tasks I need to deal with this backlog. I do not really need a “special feature” for it.
Yes. They are both useful. Date based repetition is far more common, but “periodic”, in the sense of “repeat x days after completion”, is also very useful, especially for things that are of a “maintenance” nature (haircuts, nail cuts, oil filter change …)
Periodic is a trickier feature, because it requires a linkage between the mother task and the specific instance task. Similarly, auto-inhibition or auto-trashing also requires such a linkage. Here is a thought (not a suggestion): if it is always one and the same task that keeps showing up everywhere - no clones - all this is much simpler. That is Toodledo’s approach.
The main disadvantage of the non-cloned Toodledo approach is that if you change something (a comment, a tag, whatever) for the present instance, then these changes are kept for future instances. Therefore, I prefer clones, which allow me to “scribble” or change the comments, subtasks, tags, anything, totally “safely” just only for this instance. But would it be easier for you to implement “after completion” and “auto-inhibit” if for those tasks, but only for those, you took away the “scribble” feature"? In that case, maybe such a mixed approach could be acceptable to many. Don’t know.
Overall, though, I believe most of us usually do our repeating tasks as intended. Clearing things up after a period of illness etc is something we are all capable of dealing with, one way or another. Even clearing away a whole bunch of identical daily tasks from Focus is no big deal, like in Nirvana or Doit, even though I would prefer an auto-inhibit feature. So let us not overthink this. The main focus probably should be on making the normal task management as smooth as possible.
The current “project approach” to repeating tasks strikes me as counter-intuitive and “clumsy”. I prefer to have the subtasks be actual subtasks, not a stack of completed or uncompleted instances.
I find these features useful:
- regular subtasks (not a list of instances)
- date based repetition, which you already have
- periodic repetition (x days after completion)
- auto-inhibit repetition (if the previous task has not been completed)
- since date (date of first uncompleted instance)
- ability to scribble/modify (cloned instances), which you already have
- always a “next instance” clone available in Scheduled for “scribbling” in advance. Doit spawns the clone one day before and Nirvana and GTDNext only on the scheduled day itself. Ideally, I would like it spawned immediately upon completion of the current instance (or even earlier), for example in order to add notes (subtasks) to my next monthly Pay Bills task for non-standard payments.