From a review of Dan Ariely’s The Upside of Irrationality:
Ariely points out that adaptation can be slowed or even prevented through intermittent exposure to the underlying stimulus — that is, if you take a break, the emotional sensation comes back with nearly full force.
Here’s where our intuitive response is really wrong: we have a tendency to indulge our pleasures without respite, and to take frequent breaks from those things that make us miserable. This is exactly backwards. If you want to maximize your pleasure — a great dessert, the delight of furnishing your first real apartment after graduation, a wonderful new relationship — you should trickle it into your life, with frequent breaks for your adaptive response to diminish. If you want to minimize your pain — an unpleasant chore, an awful trip — you should continue straight through without a break, because every time you stop, your adaptive response resets and you experience the discomfort anew.