The reason to include one is to 'boost marks'. The recurring symbol becomes part of the 'change' stuff and the teacher reads into that and says 'this is deep and meaningful'. Putting a good one in is very beneficial, in my opinion.
Okay, I think that we're all saying a bit of different kinds of recurring symbols...
Shirlz was using the meanings of 'stained' to describe everything around one person throughout the story to create a link. Think of 'stained' as "dirty", "marked", "contaminated", etc. The stained window is also reflected in the old man, he's old, and marked with the age of sitting there hundreds of years, staring at passerbys. He is also depicting an ancient tale that none today would be bothered to hear,
I'm thinking of a purely physical object, like a tree, and I change my perspective of it (spur of the moment, just read Sky High again):
The first time, it towered over you, like a twisted giant, reaching for the clouds. Its leaves rustled quietly in the wind, as the comforting shade gave cool respite while you played at its foot.
The second time, the longer, afternoon shadow gave the tree a surprisingly spooky light. Its bough appeared gnarled, hiding speakable terrors behind its formerly welcome embrace. The leaves, still rustling, left patchy images on the ground, taunting your imagination.
The third time. The bark feels, rather... barky. Or so your aching palms tells you. Step by step, you move towards your own everest. The sound of brittle leaves upsets a bird that was on the branch above you. The patchy coverage, once a nuisance, now give you a leverage over the unsuspecting neighbours at whom you spy upon.
Would that help a little?
And jayjay, to gain first requires sacrifice. I read too much, and discovered soccer too late. I really don't know how to crash learn creative writing, so my bet is to nick one and learn it.