Bugs aren't a huge problem here in SoCal like they were where I grew up in Florida, but I still tend to wear long pants and long sleeved shirts against sun, thorns, jumping cholla, and the occasional tick. I also carry a tick spoon, just in case I have to pick them off myself or the dog.
I am a mosquito magnet, though. If I go outside for 30 seconds in mosquito-country, I'll be covered in bug bites even when nobody else is getting bit. So if I'm going anywhere that has a potential for mosquitoes, I break out the DEET. 20% for normal places, 30% for more tropical locations like Central America. I spray exposed skin and the edges of my clothes (sleeves, pant legs). Literally nothing else works to keep them off me.
I tried things like the Thermacell gadget when I was back in Florida for a year, but I might as well have just hung an Open for Dinner sign, because it didn't do a dang thing. Even if I was sitting right next to it in still air. Same for citronella or non-DEET sprays like Skin So Soft (picaridin) or lemon-oil/eucalyptus sprays. I've had permethrin treated clothes, but they didn't help much either. They'd just bite my exposed skin instead. Hands covered in bites.
I wish they made something like Frontline (topical flea goop for dogs) for people, I'd be all over that. Ha.