While we do give estimated times for how long wax melts should last on our product listings, it can differ between each scent, and the type of burner you use can have an effect on how long your wax melts will last.
Scents are made up of notes, high, mid and base. As you burn your wax the fragrance is essentially 'burnt off' slowly and the fragrance fills the room. The first to burn off are the high notes, then mid, then base, so scents that are full of high notes will likely not last as long as fragrances that have deep mid and base notes, or a complex blend of all three notes. You will find the more complex the scent, the more it transforms as time goes by.
As for your wax melt burner of choice, the hotter the burner gets, the quicker the scent will burn away. Tea light burners are known for being quite hot in comparison to most electric wax melt burners, this isn't necessarily a bad thing, you'll find by using a hotter wax melt burner, the fragrance will really pack a punch. As for wax melt burners that do not get quite as hot, the scent may last a little longer, and while still incredibly noticeable, it will be a little more subtle than if it were in a hotter burner.
We give an estimate, because while we do test out our scents in both tea light and electric burners, there are so many burners out on the market we can't test them all.