How do people think about either how many extras to put into a shipment or the value of the extras to put into a shipment relative to the number/value of beers in the trade?
It varies from trade to trade and what you and your trade partner agree to. I always mention extras in discussion
Id say it really depends, for the most part I usually include 2-4 extras, in my last trade we agreed upon 2 beers and I sent 6 extras.
For me, I try to send at least 3-4 beer units (12 oz. units) of extras regardless of how big the trade is. It is not the value/number of beers traded but the type of box I have that determines my extras. For example, if I am doing a single 1:1 trade, I will usually include two extra bombers (4 beer units) to fill out a three bottle shipper. If I am doing a three bottle trade and have a six bottle shipper, I will fill out the remaining three slots with extras, which could be somewhere between 3 12 oz. beers or 3 bombers (6 beer units). My extras are either high quality locals, high quality out of distro, and/or Wants. The key is don't think about it too much and send good beer. Also, nobody ever regretted sending too many extras. I also always assume extras in a trade even if not explicitly discussed. I also usually send at least 1-2 extras in trades where no extras are agreed because I have too much beer and we have so many good locals that need to be spread around the country. The other party never complains.
I fill up whatever box I am shipping in... Typically it is a 14"x14"x14" or a 16"x16"x16". I have 6x 22's going out on Tuesday... But I have room for 3x more large bottles in the box. My target will be getting 9+ vessels.
I did an IP with @tjohn2401 and I must say: I brought one mediocre extra when he brought two great extras. Totally my bad, but we agreed we would get together for a tasting locally, and I'm pulling out all the stops. Long story short: blast em with extras so you don't feel like an ass like I did. :/
It depends what size box I have onhand. I'll just fill it up. As for the value... as long as I've had it once before, I dont care about rarity or value. I'll extra that shit!