I vape 50/50 juice in Kanger T3S and Protank 2 minis. They go about a week when I mostly vape light fruity and icy or menthol in them. Maybe 2 to 3 days if I vape a custard,coffee, or chocolate mix. I usually soak the used heads in vodka for at least 30 mins then pat dry & blow off the excess before I dry burn them. Usually after 3 weeks I'll replace or rebuild them if time permits. Like Sthur said the darker flavors will gunk up the coils faster.