I dug out an older S&W instruction manual from one of my boxes, dated 4/87. It contains an ammunition chart for the various models offered at the time.

For the steel J-frame models listed (36, 49, 60, 649), standard pressure .38 Special was listed as allowable; however +P and +P+ showed an asterisk. The explanation at the bottom of the page contained S&W's standard warning concerning these loadings.

The same chart showed that BOTH +P and +P+ was suitable in the various K-frames chambered for .38 Special (10, 15, 64 and 67)! Considering S&W's warnings about +P+ ammo I did not expect to find that.

That being said...

Among my accumulation I have both a 36 and 49 no-dash along with a 60-4. I have no personal problem shooting +P ammo through any of them, nor in any of the newer J-frames I own. At the range they mostly see standard pressure ammunition with smaller amounts of +P. My .38 carry load is the popular Speer 135 gr +P GD.

I don't believe that the small quantity of +P these guns see to materially reduce their life span. Frankly I suspect they will all still be ticking when I'm long gone...