Are there any examples of the PLAN retiring vessels early?
In my time here, it seems to me that they use them, and keep them upgraded, right up until their designed OOS date.
For ships Frigate-sized or larger, they can still use antiship missiles and ASW helicopters. These are capabilities which just need a platform to launch from, and which existing naval battlegroups (with area air defence systems) can benefit from.
If required, it's relatively low cost to install a Type-054A Frigate-level sensor and weapons fitout.
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But I'd say some of the Type-056 vessels are being retired early with the current transfers to the Coast Guard. I've outlined previously how I think there is a mismatch between the large numbers of Type-056 which could benefit from more Type-054A Frigates as part of ASW groups with 3-4 ships.
And when the Type-056 programme was approved (back in 2010?), it was likely conceived as a low-cost replacement for the many Type-037 ships as the overall plan for a largely green-water navy.
Many of these Type-037 were over 30 years old and almost certainly past their design lifetimes. But it does look like some of these were retired early at 22 years.
And since 2009-2010, China's economy has roughly tripled in size and China's ambitions have expanded to a primarily blue-water navy.