Sam asked... I agree in having lots of magazines, but what do you think of fewer mags and lots of spare mag springs and followers? This means less cost and less storage space of course and it is another way we might reduce our prepping costs.
[To recap I personally like to have 20 magazines for a defensive rifle and 10 for a defensive pistol. These are minimums PER GUN. Less for non core weapons, hunters, plinkers, etc]
To answer Sam's question we need to discuss the reasons for storing extra magazines.
If you are reading this blog I probably don't have to make a hard sell as to why you would want to keep a stock of magazines. Fundamentally they are a semi disposable item that are essential for the full operation of firearms. Without a magazine a semi automatic weapon is an awkward single shot. They are useful for all kinds of nasty survivalist scenarios. It is prudent to be prepared in case of some kind of future ban on politically incorrect magazines. This has happened in the past, most notably from 1994-2004. I know a guy who paid $160+ in 1990's dollars per magazine for some stuff he was caught short on. Also magazines in general and particularly military surplus type magazines can decrease in availability over time and prices of mags are not going down any time soon.
Now let us look at the reasons we might find ourselves raiding the stash of magazines we have to supliment those in our general load out. The first would be to replace magazines that we have been using which are no longer servicable. A mag wears out or breaks and needs to be replaced. Mags can wear out of break in a variety of ways. Springs can wear out and feed lips can be damaged or work beyond use. Bottom plates or mag bodies can break. My anecdotal observations show that rifle magazines usually fail by worn/ damaged feed lips or worn out springs and for pistols it is usually springs or mag bodies.
The next would be replacing magazines that are lost or misplaced. In fights or tough realistic training that require reloads magazines can get lost. Maybe you can't conveniently put a mag into a pouch or pocket or they fall out and either you can't come back and look or they get lost in the brush. Occasionally a mag could be left at the range or whatever. These things don't happen a lot but they do happen. For me the culprit has been misplacing magazines. A mag gets put in a backpack or a drawer or whatever and gets forgotten about. Once I was moving and emptied out a closet to find aproximately 15 magazines and 500 rounds of ammo. If you only have a few magazines, particularly in an environment where they are difficult or impossible to replace this sort of thing could be devastating. If you have a healthy stock of magazines it is just mindly inconvenient.
The last reason would be the all encompasing "other". Other could be deciding that you want to carry four magazines instead of two. It could also mean deciding that you want to keep some loaded mags in the car or at some alternate location. Maybe you have a friend (who uses a compatible gun because you are smart folks) is caught at your place and things get hairy or they don't quite do the best job of preparing and need a hand.
So back to the question at hand what you think of fewer mags and lots of spare mag springs and followers? No, I don't really recommend fewer magazines and lots of springs and followers (on a tangent I have never seen the actual follower really fail). The numbers I recommend are what I decided were good based on my experience and overall situation. They are what I personally use. Buying a lot of mags sucks, even relatively common and inexpensive ones add up in cost fast but it beats getting caught short.
That being said I suppose one could reasonably decide to get a couple fewer magazines and store some spare springs as long as it doesn't get too extreme. If you get maybe get seven pistol mags and 14/ 15 rifle mags and keep some springs around that would probably work. However I certainly wouldn't suggest only having three pistol mags and eight rifle mags with extra springs. The reason is that spare springs really only cover you if the spring on a magazine wears out, not if other parts wear out/ break or the whole thing gets lost. Also extra springs do not equal extra magazines. Furthermore low levels like that would make you too vulnerable to the damage or loss of a single magazine and give little ability to have a heavier load out or cross level/ trade magazines as needed.
I hope that answers the question or at least gives you something to think about.