Unavoidable timers. For example:

1. Devices with low battery and the charger is out of reach.
2. Drinking a bunch of water.
3. Playing an album with nothing queued afterwards.

Along the same lines: incidental timeboxing. My toaster takes 2 mins, and leaving the kitchen means I'm likely to end up with sad cold toast, so I better stay and deal with some of the kitchen mess in those two minutes. The phrase "if you have time to lean, you have time to clean" has been strangely useful to me.

Allowing things to be partially done, but not in a state where is going to be a big problem. For example, the above kitchen mess.

• A cup and bowl with food left in it will be hard to clean and attracts bugs and grows mold, and that's a problem.
• An empty but dirty cup and bowl is better but still harder to clean.
• A rinsed cup and bowl filled with water left in the sink is easiest to clean, so that's the least problematic state to leave it in, and it's not much harder to do that than it is leaving the food-filled cup and bowl there to begin with.