Originally Posted by Rowan
Finally, be careful with your bike shop. The comment about an entire shifter/derailleur/chainring replacement sets off the alarm bells for me. Get a second opinion from another LBS if you can.
I second that. Unless the chain rings are very worn, which is hard, they should last tens of thousands of miles. If you do need to replace the shifters, try to get the "trigger" type. They work a little better.
Remember to change your chain when it "stretches" 1/16 of an inch. Most people recommend changing the chain AND cassette when the chain has "stretched" 1/8 inch, but if you change it at 1/16, it doesn't have a chance to wear out the cogs on the cassette.