One lens or two for a trip?

Here is what the site says about that.

From Lenses: Primes or zooms: - Zooms are flexible: one lens covers many situations, and you don't miss shots changing lenses. - Primes (fixed focal length) are smaller, sharper for the money, and much faster. A 50mm f/1.8 gathers far more light than any kit zoom, at a low price. Most people end up with one or two zooms and one or two primes.

From Travel: Common mistakes: Buying a big kit for a once-in-a-lifetime trip, then carrying it once. Taking a camera you've never used on the trip itself: buy it a few weeks early and learn it at home. And forgetting that a wide lens matters as much as a long one in old towns with narrow streets.

Quoted from this site's pages.