Best insect repellent for travel: what works and how to use it

Confused by insect repellents? This traveler’s guide compares DEET, picaridin, IR3535, and oil of lemon eucalyptus (OLE/PMD), explains concentrations and reapplication, when to choose each (mosquitoes vs. ticks), how to pair skin repellents with permethrin-treated clothing, and what to pack for trips from tropics to trails.