I hear the question often 'What should I upgrade on my bike?'. Much of the time, someone is planning to spend drop $100 bucks on a carbon stem that will save them 20 grams. Or maybe $400 on cranks or a fork that will save them 50 grams.
Those things are cool. They add some bling to the bike, but I can guarantee you that in the flat land that we live in (Mid-South area), 20 grams will not make you any faster, nor will 50. Truth be told, even if we lived in Colorado, those savings would not help myself nor most of the people I ride with.
So what will benefit you? After twenty plus years building bikes for others and myself, I'm convinced that the first thing you should upgrade on any bike is your contact point with the bike. You should upgrade your saddle/shorts, shoes/socks and bars/gloves.
If you ride a $7000 bike, but ride with $70 shoes bought online because they were a bargain, and they also don't quite fit you - YOU WILL BE SLOWER! On the flip side, if you buy a $1000 bike and spend good money on good quality contact points of shorts/saddle, shoes/socks and bars/gloves, all of which fit you correctly, you will be faster, you will be more comfortable, and you will recover from your ride more quickly.
So, if you are starting out and new to riding, plan on spending 50% the cost of your bike on good quality clothing, shoes, gloves, helmet, etc. If you are already riding and wanting to upgrade, take a look first at your contact points. Are your gloves or shoes worn out? Do you need new bar tape? Would a new saddle allow you to ride more comfortably longer?
One other note. A lot of people preach about buying local versus buying online- the areas I've discussed above truly are not something that should be bought on-line. Shoes and clothing must fit well, or you will be uncomfortable and possibly even hurt yourself. Your local shop will let you try different sizes and brands to find the right thing for you. With saddles, they might even have a try-before-you-buy program.
Last year, I decided to upgrade my bars on my road bike. I was not completely satisfied with the shape of my previous bars, so I bought a new set with a more modern bend and I really enjoy the new shape. This year, I decided to buy some new shoes. My old shoes are 9 years old and had been through 3 bad wrecks. They were worn out! I picked up the new shoes this evening and cannot wait to try them out this weekend.