It is about that time in my homebrew career where I switch from a fermenting bucket to a glass carboy. I have been looking on craigslist for the past few weeks to see what people are selling as far as carboys. It seems most people are looking to sell 5 gallon carboys. I wanted to see what peoples opinions were on whether or not to buy a 5g or 6.5 gallon carboy? Is one option better for the primary vs. the secondary? It seems you would have issues adding to the secondary with a 5 gallon. Finally when they refer to 5 gallons is that all the way to the top of the neck or does a 5 gallon batch leave a little space in the neck. Thanks for all opinions.