What is your cost per KWh? Here, it's about 20 cents, with taxes and fees, so 30W is squat. This is much easier than it would be if Energy Star didn't exist- 1/2 Watt in standby gets their rating and if most devices meet that, off-time is cheap but the accumulated appliance/entertainment/pumps & motor use that really adds up.
Sense sells an energy monitor that's not cheap, but it allows checking each circuit at the breaker panel. Unfortunately, it's $300 and it would take a lot to offset that. I have a lower priced multimeter that has a current clamp- I'm going to see how well that works for lower current devices. Will post the results.