prathmann
Another thing to do when you get home is to measure your chain yourself to see if it really needs to be replaced. Bike chains are exactly 1/2" long per link, so if you hold a ruler up to one the pins should all line up nicely on the 1" and 1/2" marks. The way to tell if a chain has become too worn is to line up one pin with the end of a ruler and check to see that another pin about 12" away also lines up right at the inch mark. If it's off by 1/16" or more then it's time to replace the chain.

By the time the chain wears enough so that the measurement over 12" is off by over 1/8" then there may well have been enough wear on the cassette so that will need to be replaced too. But I would always first try just replacing the chain and seeing if there's any skipping before changing the cassette.

idoru2005
Bike mechanics, like auto mechanics and doctors, are prone to telling customers that something needs to be "replaced soon". It's how their employers make money.