I don't think there should be a hard and fast rule, condition issues excluded, with the exceptions of the obvious (i.e. always buy Kiton, never buy Stafford). There are just too many factors that go into whether or not something will do well: brand, size, pattern, age, etc. I still end up always buying more than I know I should, usually just because they're cheap. You can count on most shirts from VV, Southern Tide, Gitman Vintage and, even still, RG to do reasonably well.