How much money have you spent on modifications to your gun? We all appreciate a nice trigger, hi-visibility sights, a smooth action, and the list goes on and on. Now the more important question to ask yourself is if you've spent as much on modifications as you have on ammunition and training.
We certainly don't mean to imply that there's anything wrong with modifying a gun to better fit you, your needs, or how you want that gun to look and perform. However, in this age of "Gucci Glocks" many people get so caught up in modifying their gun that they forget to take it out and shoot it. There's no perfect ratio of dollars spent on upgrades to rounds fired, but gun upgrades are a realm of diminishing returns. There's only so much you can do to change a gun, but there is ALWAYS something you can learn to do better, smoother, faster, more efficiently, etc. Even the best gun in the world is not going to make a novice shooter into a competitive master, much the same way that a Formula 1 car does not make a skilled driver. A masterful driver can reap the maximum performance from a car built to perform, but will also drive circles around your average driver in a basic sedan. The same concept applies to firearms.
To get the most out of your gun, regardless of it's level of modification, nothing can replace training and trigger time. No part has been invented that negates the need for solid fundamentals, which are learned through training and honed through repetition. Modify your guns as you find their shortcomings, but don't forget to hone your skills to overcome your own shortcomings.
Plus... It's just plain fun!