I did, or once did, back in the late 1980s, replace leaky rusty freeze plugs, one by one as they began leaking, in a 440 e-body car. At the very end, when one of them (I forget which one) required my pulling the engine and transmission (together as one assembly) to access it, I finished out all the others I had not replaced until then.
It took me one Saturday (day off from work) to pull the engine, replace the remainder of the freeze plugs, and return the motor, hook it all back up, and drive to my local In-n-Out for a dinner burger.
I then realized if they were all going to leak eventually, just doing the nasty and pulling the motor was less work, than those times it took me a whole day or two, to replace a single freeze plug without removing the engine.
With hindsight, I realize my car was stored with plain water in it for some number of years before I was the owner. Had I known then, I would be replacing them all, the "pulling the motor" thing-deal is the least amount of work, overall.
As a bonus, I flushed out a good amount of casting sand from that motor with a bunch of freeze plugs removed. Afterwards, it ran very much cooler than it did before this chore.
The next motor I rebuild from the pan upwards, I will make an effort to flush out any residual casting sand.
