Open up before a tasting?

I consistently notice changes in even the first couple of days a bottle is open. 90% of the time they are positive. New bottles can be interesting but are not accurate representations of the spirits potential imo.

@Maltmark, most whisk(e)ys will be much better open for awhile. I would consider opening them all now. Frankly, our bottle of HP18, and, if you read through the discussions on Connosr, those of a few other members, required a period of months to reach their full flavour. Ours took 3 to 4 months open to be at its best. I would not expect your HP18 to be at its best in 2 weeks. You could also try some of @A'bunadhman's decanting techniques to try to speed it along.

Heartily agree with mattsteg and Victor, and I would add that I've experienced dramatically different changes with different whiskies. Some seem to change just a bit with time after opening, and others after several months become nearly unrecognizable compared to the day they were opened.

The most significant change I noted was Bruichladdich Islay Barley 2006. My first bottle had been open about six months. I poured the last bit and was amazed at the change--all for the better. Then I opened a new bottle and tasted it. No comparison to the last sip out of the first bottle so I've let it be for about four months. I'll got back to it in a few months, but I don't expect as dramatic a change as I experienced with the first bottle because of the high volume in the second bottle. Fun to experiment and discover these things.

Thank you for all of your input. Very insightful and helpful.