For those who are wondering, these figures come from weekly utility meter reads (gas, electricity and water), an indoor/outdoor thermometer, petrol receipts and log book (I have to keep one for tax anyway), a thermometer in the compost and a sheet for keeping track of eggs. (The new girls are yet to get started on that front!). I use a spreadsheet to keep track of things and have it set up to automatically generate summaries and charts. We find weekly record-keeping more helpful that just a quarterly bill (by which stage you can't recall what may have contirbuted to the outcome).
Although you may not choose to record this sort of data on an ongoing basis, even in the short term it can give you valuable feedback as to how you are tracking. For example, even without a special device, doing your own meter reads can help you identify and address problem areas.
Of course each home, its occupants and various other factors are different. We're including these numbers not for direct comparison (we're better at some things, working on others) but just to note what we're keeping track of. We're interested in the opportunities that observing can bring - allowing you to hopefully understand why a figure is what it is, and to make adjustments if greater efficiency is possible.
But what about the garden?
I keep fairly informal records of what we harvest from the garden, as part of a garden journal. This started as a fairly messy collection of notes on the backs of envelopes, and the like, but I've moved to keeping it electronically, rather than just paper-based, in the past year or so. The main advantage of this is that it's searchable, editable and more easily organised. I still often take notes on paper, but transfer them across by either scanning them or typing them up.
I find a digital camera invaluable for recording what's happening and the crucial 'before and after' shots (although I'm often half way through demolishing or reorganising something when the thought to take a 'before' shot occurs - urgh!). I've even been known to use it to help identify pests and diseases. Into my journal I also put links to resources that interest me and of course pictures of gardens or buildings we've visited.
It sounds like a lot of recording, but generally it's done fairly quickly and it's a million times better than just hoping I'll remember (because I very rarely do!). It's also a fantastic resource for both looking back at and dreaming of 'what's next', not to mention remind me that even when it feels like we're moving at snail's pace, there really has been a lot happen in and around our little house on the hill already!