[Gardener2]

I'd probably write this as something like:

Project: Form habit of using Nectar card.
Next Action: List Nectar-qualifying purchases for next week. (Repeating, Weekly, Fridays, context Home or Computer or whatever seems appopriate.)

Or, of course, whatever other action I thought would help me form the habit. Another possible task might be writing a list of Nectar-qualifying brands for normal everyday purchases and keeping it in my wallet every time I shop.

(Edited to note: Oh. _Online_ shopping. Well, you get the idea, anyway. :))