I don't. Why would I want to upgrade my fixtures twice a year if they're working and look fine? I'd be happy to keep the same set for 20 years, myself.
Is it really worth carrying a metaphor out to its absurd conclusion? A web browser does not exactly equate to a plumbing fixture, yet they both have maturation cycles that prompt people to upgrade over time. Browser technology moves faster than plumbing, I don't think anyone would be terribly surprised by that revelation, yet when plumbing technology advances I will upgrade. I will upgrade sooner rather than later because the savings in time and energy pay off over time, just like with browser technology. The further behind the cycle I remain, the more it costs me to modernize in the future and the more it costs me to stick with the old. The literal time period is completely irrelevant.