How long to go from idea to execution for a trip?

I wish I could say in a moments notice. Reality is, we had a mouse problem once and now take all clothing and perishables out. So even our fast weekend trips we usually like a day or two notice. It seems, on average, we have 4-5 hours of work involved for any trip.

Then there is our long (6-7 weeks) summer trip each year. For those, the packing doesn't take any longer, but the planning is usually a year in the making, mostly due to reservations.