I have had a kilo TT pro for about 6 months of fairly heavy abuse. I would wager that I have about 1000 miles on it, through all kinds of weather.
When I bought it, I had a LBS strip it down, lube everything, and reassemble. I replaced the pedals and the lockring. Flipped and chopped the bars, and everything else is stock.
It still rides smooth, no mechanical problems.
I think you should only replace components that you want to because of fit or aesthetics.
Ride it 'till something breaks.