Measuring for shocks and how to ask for them?

How do you go about measuring for shocks? And when I go to the shop to get new ones do you just have to tell them the length you need? I dont want anything fancy so I will most likely got to AZ or Checker (yuk) but I am afraid they will be no help and will just want my vehicle info. That doesnt help when you are lifted. Can you just tell them how long/short you need them?
Brett

You need to know the travel distance, compressed length, and extended length.
Some of the suspension manufacturers list that info as well as shocks for specific suspension heights.

Depending on the lift...you may find that they list shocks for YOUR jeep. PepBoys lists shocks for a 3 inch lifted XJ.

what you can do if go in and they should have a book behind the counter, that has all the compressed and extended lengths in it. the book will also list what end is on it.