Always straight up. Take your time, two fingers should last as least as many hours. The alcohol will slowly change character over time (absorbing water from the air). You'll get different notes and aromas from start to finish.Well I found glenlivet 12, it was $47 for a bottle of first fill 12, the regular 12 was $45, so I got the first fill, it was only $2 more. How should I try it, on the rocks or just straight up?