Some boutique ammunition makers' +P .38 Special loadings aside, most +P .38 Special ammunition being sold isn't worth the amount of ink it cost to print "+P" on the box, as it consists of light weight jacketed bullets loaded to weak and watery velocities.
After reading of +P dithering for years, on this forum as well as other forums, I "took one for the team" and once experimented with some +P .38 Special ammunition in a ratty ol' 1904 vintage Military & Police kept on hand here.
Ammunition from two boxes of different lots of factory Winchester +P 158 grain lead semi-wadcutter hollow point ammunition along with one box of Remington +P 158 grain lead semi-wadcutter hollow point were fired and chronograph tested. A handload of 5.2 grains of Unique under a cast lead 158 grain semi-wadcutter was also tested. 40 rounds total were tested in 10-round strings.
The revolver handled the tests with aplomb.
The revolver was inspected before sitting down to shoot it. Despite its shabby appearance it was tight and mechanically sound with a good bore. After the tests it was inspected again. No cracks, bulged cylinder walls were observed and the revolver and it remained as tight as before the tests.
No precision measurements were taken of the revolver before and after. No magnafluxing was done. It could blow up the next time it's fired, but I'm confident that it won't.
It's seen some range use and plinking sessions in the years since the tests and always gives complete satisfaction for the purpose.
A 1921 vintage Colt Police Positive Special and a 1914 vintage Colt Army Special have also been subjected to limited +P test with the same loads. They didn't rupture a gut either.
Everything "vintage" is "collectible" these days and it's not considered expedient to subject one's high condition vintage revolvers to shooting use. Still, the revolvers will take it.
I'm not going to subject the now 118 year old revolver to a steady diet of "real" +P ammunition, but then I'm not subjecting any .38 Special here to shooting large quantities of +P ammunition. I'd use +P with no hesitation in a pinch if an emergency dictated it.