Re: How many open bottles do you normally have?
I've only recently decided that SMSW is my favorite alcohol, and subsequently occupy the bulk of my purchases, so I have just six bottles of Scotch, all of them opened. I don't see the point in buying a bottle and not opening it, not at this early stage in my drinking career. If I'm going to buy another bottle, it's going to be a brand I haven't tried yet, or another bottle of a brand I just ran out of. In either case I'd open the newly-purchased bottle.
I have a few blended malts, but only in pint sizes. I never met a Scotch I didn't like, but I prefer single malts, so I don't plan to buy a 750ml bottle of blended ever again.
Laphroaig 10 CS
I will probably buy Ardbeg 10 and Highland Park 12 next, this weekend most likely, and I'll be opening both of them right away.
I do worry about deterioration though, so I aim to keep my open bottle total in the single digits. If possible.