Recently I have been painting small flower studies. Choosing a single subject and relatively simple composition means I can really work some things out in a shorter space of time, and I can also experiment with different surfaces and approaches. Each painting has its own point at which it is "finished".
As the great painting teacher Hawthorne said:
" Painting is like an after dinner speech: Get up, say what you want to say, and sit down again"
With this one, Roses, 25 x 20 cm I went quite far, achieving a high degree of what some might call "finish". WIth others the finishing point came earlier in the process. But of course its not about finish; it's about the quality of attention you have up until the point that you stop.