Money note, since nobody else says it out loud: the whole thing cost less than a takeaway dinner, and most of the supplies came from the drawer I was about to throw out.
I tested this for a month before writing anything. Three takeaways survived contact with reality: it is cheaper than it looks, it rewards consistency over intensity, and the boring option is usually the one that works.
Have you tried it yourself? Tell me in the comments — I read everything.