I’ve been going through my catalogue of unpublished stories this last week and revising them. One or two might fit an open market, but not all. Once I’m revising, I kind of keep at it.
The distance of time helps me to consider my own work more critically, so if there is a reason to do it for one, I might as well do it for all. That way, at various periods, I am reviewing all my work. The chances of this stuff getting published is honestly declining as markets for heroic fantasy (that’s the only genre in which I have completed, unpublished stories) are likewise declining.
I do a lot of my proofing on printed pages. I am comfortable editing other people’s work on the screen, but for my own work, I find I’m better able to spot problems on a physical copy. Can’t say why that is, and it might actually be psychological.
If I have the time and motivation, I’ll read these stories aloud to myself. Something that looks fine on the page or on the screen might sound odd when you actually say it. Is it necessary? No, but I’d say anything that you do to make the writing stronger is worth the time.