My fridge inventory has one lonely 0.25mg pen

I keep a note on my phone for every box in the fridge: purchase date, BUD, pens left, cost per mg, and days of buffer. Current count is four pens total, but one is the 0.25 that got left behind when my schedule moved to the next strength. I paid $165 for it, shipping took six days, and it expires in late March. My spreadsheet says it’s basically $41 per mg, which hurts to toss, but my shelf space and my brain both want it gone. I’m not looking for dosing advice — just curious how other price-trackers handle leftovers. Do you treat older pens as emergency buffer, or do you clear them out once the next strength is in rotation? I’m trying to decide whether keeping it is practical or just hoarding with extra steps.