As a guy who has logged more takeoff and landings (as a passenger) than some commercial pilots, I can tell you why you should avoid checking bags in the way you should avoid a swarm of angry bees.
1. It adds - significantly - to your door-to-door travel time. When I fly, I go with my boarding pass in hand (printed at home or in the office) and I go directly to security. I can and do arrive 45 minutes before my flight - routinely - and make my flight with time to spare. It's more important on the landing part. I get off the plane and keep going. Waiting for your luggage to arrive can be a 45 minute debacle.
2. Lost Bags. They say it does not happen much. It's happened to me more than a few times, most recently when I went to Cyprus and my bags went to Zurich - for FOUR DAYS. I arrived for a business meeting after flying from NY to Amsterdam to Budapest to Cyprus in the same rumpled clothes I was wearing when I got on the plan at JFK the day before. I ended up spending hundreds of dollars to buy new clothes in Cyprus.
3. Stolen Goods. Aside from stories like
this , I've also had items stolen from my bags in the past, and you have basically no recourse.
4. Extra Bulk. Lighten up! My family went to Disney for a WEEK and we only packed our rolling carry-ons, nothing more. You don't really need to bring too much, and you can - gasp - do laundry at your destination if you are going to be there a while.