Would be great to have task statuses, like "waiting", "in_progress", 'sometimes'.
Tags are bad as 1. you don't want to clatter your other tags, 2. With tags you should manually "remove" statuses. Like, a task can't be both "in_progress" and "sometimes", so only one status should be allowed. One can use locations for that, but 1. locations should stay...well, locations. 2. it's not easy to change locations, there's no easy one-button way like for changing lists or tags. So, I think a new status entity is a must-have