The OP wrote: I know on the old meta, now known as tea, such issues were discussed. I am collecting here some relevant threads which I was able to locate. I am making this CW - feel free to add more links, if you consider them relevant.

• Editing old answers by other users; François G. Dorais said there: "It's fine and encouraged to improve old questions and answers. However, keep in mind that it's mildly annoying to have many old questions bumped up to the front page at once, 3 edits per day is acceptable."
• Must we raise the dead for umlaut's sake; Gerry Myerson's advice: "Re-tag two or three questions a day until they're all done."

The OP wrote: I know on the old meta, now known as tea, such issues were discussed. I am collecting here some relevant threads which I was able to locate. I am making this CW - feel free to add more links, if you consider them relevant.

• Editing old answers by other users; François G. Dorais said there: "It's fine and encouraged to improve old questions and answers. However, keep in mind that it's mildly annoying to have many old questions bumped up to the front page at once, 3 edits per day is acceptable."
• Must we raise the dead for umlaut's sake; Gerry Myerson's advice: "Re-tag two or three questions a day until they're all done."