Yes and no.
There IS no true expiration date of our oaths of office, no outprocessing step where you take back your oath.
NOT everyone can or will be recalled, but in general, anyone over the field grade rank of 04 (Major in the Army, AF, Marines, LT in the Navy, etc) can be recalled to active duty.
Back in Desert Storm II, 2003, I worked with a 66 year old psychiatrist who was recalled to AD after nearly 15 years out; another, an orthopedic surgeon who lost his practice, hospital board position, marriage, everything when he was recalled in Desert Storm I 1990.
I’ve never seen nor heard of an enlisted guy being recalled, but I imagine it could and has happened.
I knew a guy who retired as a Major in the USMC on 9/1/01. He was recalled the Wednesday after 9/11.
For enlisted when you retire you are transferred to either the Fleet Reserve or Retired Reserve. During this time you are obligated by your oath and eligible for recall but only with Congressional approval. During that time you technically still fall under the UCMJ and can be recalled and charged.
After thirty years you are transferred to the “Retired List.” Your obligation has ended and you are no longer under the UCMJ. You cannot be recalled from the Retired List.
Officers are a whole different set of rules. There are limits and do require in some cases congressional approval. My understanding is no service can have more than 10 or 15 General Officers on active duty at one time.
Had an incident few years back, forget the particulars but it had something to do with the way I was dressed. I think I had just left the gym or track and had sweats on in the Exchange. A man approached and said I was not properly dressed. I politely told him to stop bothering me, he said he was a Major, I responded “I’m on the “Retired List” so I could care less.” Or words to that effect. Left him speechless, I thought it was funny.
I always knew that I could be recalled, but after so many years out, I figured it would never be done. They would have to completely retrain me and I figured they would rather spend the money training some young buck and not waste time on a broken down fat man.
A bunch of the old guys from WWII and Korea came back in as contractors to show all the Gunner’s Mates how to operate the 16” Guns on the BBs during Desert Storm.