I see lots of posts where people are asking about what ammo they should buy to practice with. I don't really understand the concept honestly.

I have several years of ammo stored away. Every year I buy more. As I buy more, I shoot the OLDEST of my stored ammo- I'm on about a 10 year cycle roughly- I'm shooting Today what I bought about ten years ago..... I recently found some South African I had misplaced and blew through that but most of what I am shooting right now is Guatemalan.....when it runs out it looks like I will be shooting some Winchester Q3131. I buy good ammo- M193 spec, always, and then stack it away. As I need ammo I shoot whatever is next on the shelf....

Do most people not rotate their ammo or do they just not store much?

As weird as it is a lot of people don't keep any on hand.  They shoot it up at the range then have nothing until the next time they go to the range.

But "practice" ammo just means cheaper non duty type ammo.

I try to keep a minimum of 1000 rounds (not counting reloading components) on hand of FMJ and a few hundred "tactical" loads around and rotate it out by age like you.

But it gets expensive trying trying to keep it up when you shoot alot.

I run about 400 rounds of 5.56 a month- 100 a week, plus one or two classes per year. I try to keep 6,000 rounds of ammo on hand per year of shooting. I don't know why it should be expensive- it's actually CHEAPER in some ways...... I try to make one large ammo purchase per year-to replace what I know I will shoot out of storage....the ammo I'm shooting right now....was ONE HELL OF ALOT CHEAPER than the ammo I'm buying to replace it! Which means I have cost averaged the ammo I am now purchasing.

Some people consider practice ammo to be the cheapest thing they can find, Wolf etc.  I buy the same practice ammo you do.  it can double as defense ammo.  But I also buy MK262 that would be used in a defense situation.

I have a pretty decent stash of Black Hills and CBC MK262. I also bought a bunch of the Palmetto Black Hills 75 Grain blue box ammo when they had it at $29/50...anything Black Hills is good shit....I don't shoot as much of this ammo as the M193 but I do rotate it out regularly as I find decent replacement ammo....

I have a friend who only keeps enough ammo on hand to keep three mags for his m&p40 loaded. Some folks just don't believe in stocking up.

If I was to use the words "practice ammo"  It would be ammo I wouldn't use for defense unless it was the last thing I had.  I usually get M193 spec ammo as well, so don't tend to worry about this.  But recently have been considering getting some Wolf Gold just to shoot at the range since it is a good bit cheaper then full power M193 spec ammo.  But I would choose my Federal or IMI over the Wolf Gold in a SHTF/Defense situation since it has another 150FPS on it.  And if you are like me, instead of just shooting what is oldest - I would try to save whatever my rifle liked the best and shoot up the other.  For me it seems IMI is the most accurate in my rifles so I would choose IMI to save, and shoot up my Federal.  But once I find an ammo that I like i generally tend to stick with it and only stock it up so that there isn't much point of impact shift, and because I know it shoots good in my rifles.  Since I just recently got into ARs I am still trying different brands but so far my best has been IMI, with real military Lake City right behind it.  For my AKs I will only buy Golden Tiger because that is what they are sighted in with, and it just shoots so much better out of them then Wolf/Tula ammo does.  

And no I do not rotate my ammo either, it doesn't go bad.  I just shoot whatever I feel like shooting, and don't worry about what date it is.  I have ammo from the 30s and 40s that still shoots as good as new.  And tons of ammo from the 60s-70s, without one failure I can think of over the thousands of rounds I have shot from many calibers and countries.  Buy quality stuff to start with, and store it appropriately and it will outlive your great great grandkids.

TSAE223G - AE223G Federal American Eagle 223 Remington Ammo 50 Grain

Practice ammo is what shooters shoot, all other ammo is what you find at estate sales when that guy dies.  Then hopefully someone shoots it, or the cycle repeats.  

I just got done shooting some FA-61 MATCH head stamp 30-06 garand ammo that was in the factory .50 cal can all clipped up.  It shot much better than the current HXP Greek ammo.  

Thanks dead guy who stored this ammo for 50+ years without touching it!  

I would wonder what one was practicing with "practice" ammunition.  Is that just a code word for "blasting" (i.e. " making a lot of noise without any tangible benefit") ammunition?

I often "practice" with Barnaul-made steel-cased ammunition.  It's great for trigger control practice, moving ("run and gun") drills, and so on.  But I'm not practicing "precision shooting" then, I'm practicing specific weapon handling skills.  I'll point out that both Barnaul-labeled and "Monarch Steel" labeled (from Academy Sports) .223 is on the warm side of the .223 range, and has been of more than acceptable accuracy for my purposes.  I've never had a failure with this ammunition, either.

I train, practice, and plink with cheaper 55 or 62 gr FMJ (NOT M855 though), and for any defensive use it would be the Black Hills or Cor Bon 77 OTM I have. I'm not going to run 500 rounds of MK262 in a day practice session, or 1500 at a carbine course. I will run a case of XM193, AE223J, PMC, PRVI, etc FMJ though.