The last time I travelled, there was a couple standing at the check in desk arguing over what they were going to toss from their bag to avoid the extra fees for overweight luggage. They could have avoided all of that wasted time and embarrassment as people stood there watching them fight over trinkets picked up on tier trip by weighing their bag ahead of time.
If you travel a lot or have a trip planned where you expect to bring lots of stuff back, you need something like the new Balanzza Mini Luggage Scale. The little scale is digital and has a LCD screen that is backlit with blue light. The thing is easy to use and has an integrated strap for connecting directly to the bag you want to weigh.
You take that strap and wrap it around the handle of your bag. All you have to do then is pick the bag up by grabbing the scale on both sides and wait for the scale to beep. Once done you can see exactly how much your bag weighs and shed things if it's too heavy. The little scale will measure up to 100 pounds and is small and compact enough to not add significantly to the weight in your bag. You can pick one up now for $24.95.