I prefer longer to shorter, even though the time involved grows exponentially. Since I can write just for the fun of it these days (as opposed to grinding out incredibly dull technical reference manuals on a deadline, to be read by an audience of, at best, one or two), a story can take as long as needed, often stretching into years, and in a few cases decades. Waiting ten years for a serial story to conclude is cruelty in its purest form, one more reason I never use the format.
Do I carefully plot out a story in advance, crafting each character and situation with infinite care? Not in this lifetime. If one were charitable my style would be "haphazard", in that I get an idea, bang away at the keyboard to capture it, and at some point in the future wrap a story around it. That might be the far future; when I open my pinned document list in Word I get a long list of half-baked ideas waiting for more attention.
Do storylines become repetitious? Sure, just watch any TV sitcom these days. There hasn't been an original sitcom plot since I Love Lucy back in 1954. It's all about how the story is told, how to embellish the characters, the plot twists, the art direction, all the little details that make it interesting even if predictable. That's why I prefer novelettes and novels to short stories. There's more space, time, to be creative.
And yeah, it's not the ending that's difficult, it's how to get there from the beginning. I look at my slushpile and cringe when I think of the large percentage with a great ending but I haven't figured out how to get there.
That part above, about decades? It's not a joke. My grand project, a trilogy of novels, has been in the works for the last 15 years. The first is now in the queue, second ready except for that one last edit pass, and the third coming along nicely with a fresh (as in two days ago) idea. Are they great literature? No, more like proof it doesn't require talent to churn out turgid prose in vast quantity. That's why I charge fees commensurate with the quality of the product (i.e. everything in public domain, maybe if I give it away, like free beer...).
Jack Peacock