Hey all,
I started this whole adventure with a Sony A6000 and a few lenses a few months ago. While building up the lens collection, I've had some instances where the same lens was bought twice. Mostly through having bids on the same lens from different sellers just in case I didn't get one of them. Thanks to this, I have two Sony 16-50mm and Minolta 100-300mm lenses. I had thought about trying to sell them to get my money back, but I have the worst luck selling things on Evilbay.
At first, I thought it would be handy to just have them as spares incase something happens to the originals. Then I had a better thought, and now use them to house different lens filters. One of each lenses just has the basic UV lens, while the other has a filter for a specific use. The 16-50mm has a variable ND filter for different outdoor shoots. The 100-300mm lens has a ND1000000 filter that I want to try some experiments with.
Fast forward a few months, and I managed to get a Sony A6500 and an LA-EA4 adapter for a decent price. Now the lenses act as sort of a cap set to a stage of readiness that can be snatched up for pictures immediately. If a friend or family member wants to borrow the camera, I can give them the a600 with the lens that's got the basic UV filter.
Well, that was a long winded way of asking you all what you would do with duplicate lenses. If you've got any more ideas than what I've listed here, I'm eager to hear them. It's always fun to try new stuff and I'm sure you've all had more shenanigans in this than I have. Thanks for taking the time to read this, and have a good night!
Peace,
A dork behind the keyboard