I pretty much just play at home ( except for my practice horn which I use the case for). So, I just leave 3 or so horns sitting on my Hercules stand in the house. It's easier than breaking out the case everytime I want to practice ( lazy ..convenient.. take your pick). I was wondering if that makes the silver tarnish sooner. They really aren't in harms way as far as getting accidentally dinged so this is pretty much just talking about finish and if the bell sitting on a stand so much start to bend the bell from the weight of the horn.
Remember real TM'ers flame gently