Go to the expense of something/of doing something
Definition 1 of 1
Pro Tip 1/3Financial Commitment
Used when someone decides to spend a significant sum, for something they consider important. 
They went to the expense of a designer kitchen.
Pro Tip 2/3Not Casual
Indicates a deliberate choice rather than a casual or necessary action. 
He rarely goes to the expense of ordering dessert.
Pro Tip 3/3Implies Luxury
Often suggests an indulgence or luxury, not merely a practical decision. 
She rarely goes to the expense of buying designer clothes.