This is the way I deal with tire pressures. I don't know what the tire companies prescribe, nor do I know if there is a better way.

I check tire pressures before leaving on a trip. When in the north and heading south I expect the pressures to increase and I do not worry about it because I will be going back up north in a week or so.

Ditto, when the reverse is true.

But...my tire pressures are 5 lb. greater than the book values because more inflation pressure is better than less.

I thump the duals as previously suggested, but unless I have something that compels me to do an actual pressure check while away from home I do not do them on a week long trip, such as when going to Santa Fe this year. If my tire pressures held within a couple of pounds after sitting for a month or more in my garage, I have no reason to suspect tire pressure issues on a one week trip. I do look for any damage or nails.