How to properly ID retired military personnel?

Which of the following is correct - if any? If not, what is the correct way to say it? Sgt. John Smith, Ret. Sgt. John Smith (Ret.) Sgt. (R) John Smith Sgt (Ret.) John Smith etc... Thanks! Also, is there a hard and fast rule as to which - or any, or all - abbreviations require a period at the end? Ex: Sgt vs. Sgt. LCol vs. LCol. Thank you, John. Your ears must have been burning!

Public Comments

1. I think the second one is the right example: Sgt. John Smith (Ret.)
2. When a retired Soldier signs something it is; John Smith SFC (Ret) Saying SFC Smith would also be proper, unless it is necessary to point out that he is retired. The US Army uses three letter capitalized abbreviations without periods. PVT, PV2, PFC,SPC, CPL, SGT, SSG, SFC, MSG, 1SG, CSM, SMA 2LT, 1LT, CPT, MAJ, LTC, COL, BG, MG, LTG, GEN The Brigadier and Lieutenant Generals are the only two letter abbreviations.
3. 2 is correct ALL abbreviations require a period at the end.
4. When military titles are used by members to sign their names to documents that pertain to them personally, they must show that they are in a retired status after the grade. Social and business calling cards must reflect the retired status.
5. Here is the Air Force's Tongue and Quill electronic version which many services follow. Page 176 covers this for written correspondence and I would suggest you bookmark this if you do a lot of military correspondence. It also has some other good things that you might want to glance through and when speaking it would be US (the service) Retired Sergeant, John Smith http://www.au.af.mil/au/awc/awcgate/edref/afh33-337.pdf
6. The second one is correct. Abbrivations need a period (.) at the end of them.
7. As Linda said, the second one is correct.