@shbo , the manufacturer's instruction says to dispose of the pen 30 days after first use. Since I'm only at 5 clicks, it still has a lot in it after 30 days and I may have disregarded that instruction on occasion (allegedly,... I plead the 5th). And a medical professional has implied that it is okay to do so. Before a trip, if i had enough liquid in the pen (just from eyeballing it- you will see the black rubber of the plunger come into view thru the clear plastic as it gets low) I just take the pen I'm currently using. If I think heat will be an issue while traveling to a really hot area, I will pack the box with the pen in it next to something frozen. Like I said on a previous post, I don't even declare it while going thru TSA, and never had a problem. So many people are on weight-loss injections, I don't think TSA even cares.

Yes, ask your Dr. I'm sure they will say to keep injecting while traveling, because that's what the manufacturer says and the studies covered. Since I had to titrate up my dose due to a strong side effects, and later go off it for a week, due to strong side effects (and start over titrating again), and despite all that, and only reaching 50 mcg dose, I'm still getting 12% improvement in T scores every 6 months, so I'm more relaxed about it. That said, I'm religious about injecting every day when not traveling, and fanatical about taking my supplements, nutrition and lots of exercise.
(I've left the pen at home for two separate 20 day vacations, involving multiple countries, multiple time changes during the vacay, up to 8 hours different, a travel schedule that might compromise the medication itself due to heat, (I inject at 3pm each day so it might have to be with me all day long), unclear regulations on country's website about what to bring to document the Rx, and language barriers. Just decided it wasn't worth the hassle. )