The more money you make, the more valuable you perceive your time to be — and the more time-strapped you may feel, according to University of British Columbia psychology professor Elizabeth Dunn. 
 
So wouldn't it stand to reason that if you use some of your hard-earned money to buy yourself more time — for example, by paying someone to clean your house or mow your lawn — you might feel happier? 
 
Indeed, that was the primary finding in a series of studies by Professor Dunn and other researchers published in the Proceedings of the National Academy of Sciences (PNAS).