I'm more likely to splurge on activities than on accommodations or food, and more likely to splurge on a particular activity based on how unique it is or how likely I am to have that opportunity again. For example, when visiting Alaska, I'll stay in a motel 6 if it means I can do a flightseeing flight with a glacier landing.
I figure in 10 years I'll remember the flight more than I would remember staying in a more upscale lodge.