Mainspring?
The mainspring is the hammer spring. The long one underr the barrel is the recoil spring.
I have worked on many (thousands) of 1911 pistols from WW-I and earlier to date.
There were very few times that a hammer spr8ing (mainspring) had to be changed. Often, it was changed to accommodate the shooter's desires because he carried the pistol with a loaded chamber and the hammer down. I have never observed an early 1911 that failed to ignite the primer with the original hammer spring. Some were fairly weak, but none that I worked on, if of original length, i.e. not clipped by the shooter, failed to ignite a primer.
The recoil spring is another story. Most of the old timeers from the Great War didn't believe in changing anything, and many frames were badly battered by weakened recoil springs.
Look for yourself. This kind of mayhem leaves a distinctive mark from the spring guide.
Many of the frequent recoil spring changes are done under a cover story, to prevent the competition from realizing that special loads are being used for different courses of fire.
Some professional shooters change springs because they want to go into a match or out onto the street with everything in pristine condition. These folks are possibly compulsive/obcessive, but their equipment is in top shape.
Full length spring guides are necessary when a pistol is equipped with a bull barrel. All of mine are. The added weight at the muzzle allows fast double and triple taps and I prefer the extra weight to a compensator for street carry, duty carry and general use. The compensator has its place.
The hard variety of buffer will prevent damage to the frame if a recoil spring loses its tension, or if heavier loads are fired. Obviously, one has to check it every time the pistol is cleaned and they should be replaced if bashed down. I have used the soft variety before the hard ones were introdlluced, and never had a problem. Hey, the cost is only pennies, and they come in multiple packs. I always keep several packs with my cleaning kit.
I have a device to hold recoil springs and a scale (from Brownells) and I check every recoil spring in every pistol that comes into my shop. Those not up to spec get changed.
As for the full length guide rods used with standard barrels, they have a tactical advantage if the pistol clangs like a cowbell when moved from side to side. They were designed to be used with the early style compensators. On uncompensated pistols, they don't do any harm. If you have to press-check to determine if your pistol is loaded, you don't follow the rules. Every gun is loaded, remember? It is easier (and safer) to grasp the slide in the "fanning" grip and slightly open it to determine whether there is a case in the chamber. (fired case/broken extractor on the last round) If you have to press check you are also probably compulsive/obcessive.