Yep, okay so it's self-created and fine tuned over the years with the help of various Ts.
I get major depressive episodes where this is particularly helpful. For a few reasons:
1) function is a much simpler way of assessing "how am I today" if "how am I feeling" doesn't compute for you when you're becoming unwell
2) it's objective - so, there's no skewed results from hopelessness/helplessness issues, or on the flip side, denial/avoidance issues (like, "nah, I'm totes fine today" when that's just no the case)
3) it results on ticks on a page in front of me. Which is motivating. I can see that I have achieved something. I can also see that if I do that one more simple task? I get a better score than yesterday! Hooray! And that often motivates me where other things don't.
To make your own, think of 10 daily tasks, that range from super simple, to somewhat harder. This is going to be very personal, and may change over time.
Simple tasks for me, when I'm very unwell, include:
1) brushing my teeth twice a day
2) showering
3) eating 3 meals of proper food (doesn't have to be cooked by me)
Harder tasks for me, when I'm very unwell, include:
8) washing the dishes
9) going for a 20 minute walk
10) doing a 30 minute yoga or guided relaxation session.
The remaining 4 - 7 options are in-between that.
These are all daily routine things. Things that will help me return to a daily routine if I achieve them, and therefore stabilise my mood.
Last step:
Write them down the side of a sheet of paper, then rule off lines for each day of the week. Leave it somewhere visible, and (literally) tick the boxes of things you've achieved today, and give yourself a score.
This works for me because, having been at the point where I can't get out of bed? There's absolutely no judgment that I place on myself if I only get a score of 1 or 2 out of 10 for 3 days in a row.
The goal isn't to get 10 out of 10 every day, it is, quite simply, to track my function (or, as your T will probably call it, ADLs = Activities of Daily Living).
For people who are going to use low scores to bash themselves up with (like, "look how useless you are" etc)? This is likely to be a counterproductive tool.
Tracking that daily, I can see how I'm going. I can also take objective data about how I'm going to my T at the end of the week (without having to actually remember any of it, it's written down! Sweet!) and they can decide "You're doing okay, keep it up", or "Shit, this person needs more support right now".