I only live about 15 min. from my vet, but I had one rescue that I was taking to see our doc. every week for almost a month -- from a very young age. Believe it or not, it has actually made her MORE social around humans!
I always take a mini plastic terrarium (smaller is probably better here) and stick a disposable heat pad to a piece of paper towel at the bottom of the terrarium. You can find them in the First Aid section of most drug stores. They last about 8-12 hours and unlike heat rocks, will not burn your little ones (however I'd still recommended placing a sheet of paper towel between the gecko and the heat pad.
I typically put a few random layers of paper towel in the mini-tank for them to hide under if they're scared and prefer not to see out.
I also cleanse each tank thorougly before repeated use and would not put 2 leos that aren't normally housed together in the same tank when going to the vet!
Hope this helps a bit!
~Linz
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2.1.2 Leos "Pico", "Ringo", Rioja-"Rio", "Lola", "Louie"
1.0 feline "Spot"
0.1 canine "Tika"