I don’t rate DNF unless it’s so hopelessly awful that I’m DNF on that basis alone. I’ve sacked off books before that just haven’t gripped me but I don’t feel fair rating them as it could be a me thing. For example I nearly DNF Bright Young Women because I couldn’t get into the first few chapters and then I reread and it ended up being one of my favourite books of 2024 
Generally I’ll go something like this (and I use Storygraph)
0-1 - absolutely dreadful, why did I waste my time, please never speak of this again
1-2 - pretty bad, huge plot holes, dreadful characterisation, poorly handled topics
2-3 - not great, either plot holes or unbelievable narrative (if not fantasy), probably won’t read further books by author, dragged, poor characterisation but had some engagement
3-4 - solid reads, good content or view points, will keep in mind future books by author, engaging read, decent characterisation
4-4.75 - very good read, enjoyed or will stay with me, definitely will read authors other works and recommend books to others, interesting content and storyline, dimensional characters, will probably reread
5 - v v rare rating, exceptional writing, characterisation, plot, prose, engagement. Reserved for only a few books that I know will stay with me, highly recommended, will read everything by that author.
I think I’ve rated 4 books 5
in the last 18 months
Most sit between at 3 and 4.
Generally I’ll go something like this (and I use Storygraph)
0-1 - absolutely dreadful, why did I waste my time, please never speak of this again
1-2 - pretty bad, huge plot holes, dreadful characterisation, poorly handled topics
2-3 - not great, either plot holes or unbelievable narrative (if not fantasy), probably won’t read further books by author, dragged, poor characterisation but had some engagement
3-4 - solid reads, good content or view points, will keep in mind future books by author, engaging read, decent characterisation
4-4.75 - very good read, enjoyed or will stay with me, definitely will read authors other works and recommend books to others, interesting content and storyline, dimensional characters, will probably reread
5 - v v rare rating, exceptional writing, characterisation, plot, prose, engagement. Reserved for only a few books that I know will stay with me, highly recommended, will read everything by that author.
I think I’ve rated 4 books 5