when on vacation, I set the shipping time to something longer. It keeps me from racking up Ebay's demerits for late shipping.

I also have a trick that I planted years ago: my listings have a link to a png file that I maintain on my own server. I insert announcements like "due to vacation, all orders from January 1 to 8 will be shipped on the 9th" or "Ebay is not properly calculating combined shipping amounts - please wait for an invoice." Then I can change the announcement (or leave it blank) on my server depending on current conditions - but I only need to do it once. Admittedly, this requires advance planning to plant the code in your listings, but if you are properly equipped it makes life easier when you get called out of town quickly (as I often do).

Here's my current announcement. If I change it today, you will see its text change anywhere it is linked: