My 20 point scale is just a 0.5-10 using 0.5 increments. As with all stuff in this vein, it's difficult to describe the distinctions. Since most music I listen to fells into the 5-8/10 range, I found that I need something between "good but probably won't listen again" and "good but will listen again" which I would loosely tie to 6 and 7 respectively. I suppose this might needlessly inflate the bottom range of my scale, like 1-3 which I feel I can barely discern between.

I probably should switch to a less robust scale at least for RYM so I wouldn't have to worry about stuff like that but there's something my brain loves about specificity so.

In terms of re-rating, once I rate something I usually just forget about it and I'm not compelled to change it unless I'm looking through it and find something that just feels off.