>>In 2 weeks, I will be going on vacation for about 10 days. Do you think my gecko would be okay by himself, or should I ask a friend to watch him?

I'd have someone stop by at least twice if you can. At bare minimum, it'd be nice if they could HEAVILY mist the enclosure. Dunno what your usual feeding schedule is, but I know mine likes to eat more than once every 10 days, so if you can get them to feed the gecko too, that'd be good. Granted, they'll survive 10 days w/o food, but it'd be best to avoid that if possible.
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0.1 Albino Leopard Gecko - Tigger
0.1 Crested Gecko - Pooh-Bear