lots of truth here, i went on a hike at night with a friend recently with all of our shit. several observations i made based on this and my testing of all the crap i have:
1) if your going to have this stuff, use it. it does you no good sitting in your closet unadjusted for the 20lbs you put on since the last time you used it two years ago. if the time comes when you need it and you don't have the muscle memory it takes to reload your rifle quickly from the pouches, it will be a waste of money. people talk shit on airsofters but when it comes to what works and what will fall apart after you take it out of your moms basement id be willing to bet that the serious airsofters are more in tune than most guys who have all this stuff, but don't like to "wear it to the range because somebody will make fun of me."
2) do your research, and buy the highest quality stuff you can bear to spend on. i have an eagle pc, my friend was rocking a condor. i have nothing against the condor personally and my first gear was made up of some condor, but he was having some serious pain in his shoulders. maybe not so much from the LBV itself and more from all the extra stuff he had on it that he probably either didn't need or could have diverted to a 1st or 3rd line setup.
3) keep it simple stupid, i have 3 mags, an admin pouch with some essentials, a multitool, and an hsgi blowout kit on my pc. i have a hydration bladder that i can put on the back if i need it also. double stacking 6 rifle mags on the front of your chest, a pistol, a steel combat knife, pistol mags, yada yada yada puts a ton of strain on your back and keeps you uncomfortably high off the ground if your prone.
4) i find that wearing a war belt in conjunction with a pc is a good move, this way you take a lot of the weight and bulk off of your chest and shoulders and put it on your hips. also, having your essentials on your belt is good in case you have to ditch your heavy vest but want the ability to stay in the fight if need be.