When I travel, I find myself getting bitten by mosquitoes not when I'm outside hiking, but when I'm inside eating or relaxing or otherwise sitting still. All the recommended insect repellents I've seen (DEET, Picaridin, etc.) have warnings on them telling you to wash them off when returning indoors. I'm not sure exactly why, but slathering myself with DEET and then sitting down for a nice meal doesn't sound too appealing to me.
Are there any forms of insect repellent than can be safely used indoors? For me, it's not important if it's not 100% effective or if it only lasts for a short time. Just that it can be used inside and (particularly) around food.