How much work travel do you consider acceptable or even desirable?

I just accepted a job that would require me to travel internationally around 4 times a year (~once per quarter), 2 weeks per trip. Perhaps it's because I have never had a job that requires me to travel regularly before, I find the prospect exciting.

However, I also know that people who travel a lot for work hate it; they just want to be home to be with family and friends. For those who have experience, how much work travel is too much? What is an "acceptable" or even desirable level of work travel?