How can someone retire as an E5 or E6?

Could be medical. Could be they could never make points. Years ago, there was a policy that SGTs Promotable could retire at 20 and I personally knew someone that retired as a SGT(P) because her MOS points were constantly at 798 for 5 years running at least.

The E5s are usually medical retirements. For the Army you can stay in till 20 as an E6 and there are some MOSs that combine and bottleneck at E7. Pre 9/11 and drawdown years it was even harder.

As long as the Government has classified me as Retired, the people that don't like it can kiss my ass. I owe them no explanation. I put in my 20 years!

With all due respect sir, you are coming across as a "rank snob" Keep in mind how the enlisted promotion system works and the changes we had to endure with that system over the years. Up until 1999, an enlisted member could stay until 20 years as a SSgt. When I made SSgt in 1993, the average TIS for my AFSC was ~7.5 years. I was at 8.5. I made TSgt in 2001 and wasn't even eligible to test for MSgt until 2004. I tested and missed by 26 points and, as I was already preparing to retire, I didn't study.

Overall, I would say I had a successful career, just not stellar. Managed to survive a couple of Article 15 's and fought my weight for a number of years. But I made it to retirement. So, judge us harshly if you must, but remember, whether we were medically retired or completed sufficient service to retire, those of use who retired as E5/6 served honorably,

When your body breaks before your will to serve expires. Came back from my last deployment with severe lower back pain, x-ray showed 3 cracked vertebrae, MRI showed the cracked vertebrae along with 2 nerve sheath tumors. My options were cortisone shots to mask the pain of the cracked vertebrae along with chemo to shrink the tumors, or surgery to fuse the vertebrae and remove the tumors - both options would result in a med board and separation (running situps and body armor would be off the table - with body armor putting me in a non deployable status) after going through the IDES process the army disability rating exceeded the percentage required to retire. To be fair, I did exceed 15 years. Another thing that should be pointed out - I do not recieve cuncurrent pay, that is to say, I do not draw a retirement check from the Army, along with disability from VA. What I do recieve is 100% from VA, and 80% Combat related servicemens compensation, along with the rest of a longevity retiree's benefits (Tricare, post privileges etc etc)

Medical Retirement is how I retired. Beleive me it was not by choice.

I'll tell you about my experience in in Army,I came in when sgt promotable could stay for 20 years,then the Army changed that and had a cut off of when you came in,i missed the grandfather clause and forced to retire at 15 years and was penalized an additional 10 percent on my retirement because i was forced to retire,nice system after you have sweated and busted your bleep like everyone else,uncle sugar does what he want's to do,but how funny the following month's promotion points came out and everyone in my MOS who remained got promoted,it was a failed promotion system,that changed 2 or 3 times,sorry this may not be what you want to hear,but thats how alot GOOD NCO'S $H!t canned.

If not medically retired, perhaps Guard or Reserves?

To ask that question in the first place makes you a rank snob! There were several MOS’s in the Army that were so over strength getting promoted was a fantasy!

Honestly, sometimes a Soldier gets screwed over.