the initial class of destroyers built (ie: the first) post WWII were mostly "Charles Adams/Forrest Sherman" types which were constructed starting in the late 1950s.
These were primarily 'Gun Armed" ships and their torpedoes were for anti submarine use.
This comment is a generalization. Frigates of the Oliver Hazard Perry and Garcia class were also built and deployed to replace the aging Gearing and Fletcher classes. The latter were all gun ships excepting those that were altered to carry the rudimentary "hedgehog" ASW weapons systems.
The 30 Spruances built, according to one source, indicates that none of the class were sold to allies or retained "In Fleet Reserve".
I beleive this was primarily done for two reasons. the Spruances were built with a "modular replacement" system. This meant that many systems could be replaced easily.
As the spruances were a good "sea keeping" ship and were "easily upgraded" I beleive the Navy felt that they were best not put in a situation of possible transfer to countries who might become adversaries of the US at some later Point in time.,
Many of the Gearing (FRAM I AND FRAM II) class were easily seen in Turkish service in the Invasion of "Cyprus and the partition of the Island by force.
This did not play well with the US Public nor Our Nato Allies, The Hellenic State (Greece).
Since Turkey was also a Nato member, the situation was an explosive one at the time and held the possibilty of a partial disintegration of NATO.
Both Turkey and Greece were seen as necessary nation state components of the Alliance whose was the goal of protection from invasion by the USSR.
Also weighing in against the sale or retirment of the Spruances was the Navy's desire to have as many cruiser and destoyer types as possible be "AEGIS" system capable.
thus because of the great expense of building and manning the "Arleigh Burke" Aegis equipped destroyers (DDGs).
The Spruances were the first Gas Turbine equipped US Destroyers and thus no time was required to "get up steam". They were formidable ASW platform with moderate level gun surface armament. During the 1st Gulf war modified/updated spruances did launch Tomahawk Missiles against land targets.
The AAW capabilities of the Spruances was not generally seen as adequate given the size of the vessels and they would not have been able to defend thems selves, let alone carriers they might be escorting, in a high risk AAW scenario.
Two of the class, somewhat more heavily armed, were built for Iran. They were not completed before the Islamic Revolution in Iran, and, with a sigh of releif, the USN took them into US service in the early 1980'w.
Since surface ship "hull life" of navy ships is generally expected to be in the 25 to thirty year range, it seems clear that some further service could have been squeezed out of some of the Spru cans, but I beleive 'the urge to go Aegis" led to the decision to decommission the Spruance.
What i do not understand is why none, apparently, were put into fleet reserve given the touting of the ships amenibility to "upgrade".
However, the Arleigh Burke's who replaced the "Spru Cans" weigh in in the vicinity of the tonnage of a WWII light cruiser.
Generally it appears the Navy has taken the view "that if it ain't stealthy it better be Aegis".
Spruance next to larger sister "Kidd" (No. 993) If I recall correctly the "Kidds" wwere the larger Versions of the Spruances ordered by the Shah
Clearly this class could have served for another decade, but--------
More later on naval matters.