Occasionally I treat myself to some moderate profligacy. Having read an article about rosemary smell possibly enhancing memory, I bought a bottle of essential oil, and an aromatherapy candle holder or diffuser or whatever it’s properly called. Despite the fact that normally I would snort over a research carried on only 40 participants.
(I did snort when I later learnt I was one of a crowd. The mitigating factor is that one of the reasons I succumbed to the whim was the fact that rosemary is mentioned in the title of one of my favourite Simon & Garfunkel albums.)
I burn a candle under the oil bath daily, usually when working on my languages’ vocabularies and/or when meditating. Sure, I’ve no idea whether it actually has any effect, there are too many other variables. But the smell is pleasant, and I’ve always had a soft spot for candles anyway; somehow this makes burning one even more gratifying.