Keep it. I didn't like the lanyards that came with my V10R & L10R, some UF ones worked perfectly and still let them tail stand. No point in chucking it IMO
If you ever decide to sell it on the marketplace to try something new, having all that stuff helps the sale. Mostly I keep everything in a big box and forget about it.
I keep all the original equipment with all the original packaging; I don't know anyone who is a lanyard person who uses the stock lanyards included with flashlights..
I keep bulbs, LEDs, and parts in plastic boxes separated by manufacturer. That way if I need something I can find it. I also have a box of assorted clips, springs, and switches.
I have fishing tackle box type trays full of my spare batteries, lanyards, clips, bulbs, silicon grease, deoxit, progold
All sorted to make them easy to find
I've been using internally divided plastic cases to separate oring sizes and misc little pieces.
holsters i keep in a larger plastic container so it's all together.
I have a dedicated drawer for all my spare parts, accessories, receipts and manuals, and packaging worth keeping. It's not as neat and organized as I imagine some of the storage solutions mentioned above are, but is has served me well so far. I suspect that in a few years, I'm going to have to dedicate a larger drawer