blessing - Do married men stop saying a bracha on their *tallit katan*?

This question concerns the Ashkenazic practice.

I was always told that the tallit katan (worn under clothing, every day, starting in preschool years) got the bracha of al mitzvat tzitzit, but the tallit gadol (worn over clothing during prayers, starting when one is married) gets lehit'atef batzitzit. (The Ramah in Shulchan Aruch says we're not sure the minor garment warrants the proper blessing of lehit'atef.)

I was also told that once you get married, you stop saying a bracha on the talit katan and just rely on the bracha you'll say that day on the talit gadol.

Is that the standard practice? And where is the source please? (I looked at a shulchan aruch and saw it talked about that occasionally you can wait for the later bracha to include it, but did it say that you should?)

Answer

Mishnah Berurah (8:24) says that "in our times" it is customary to do so, and says that indeed it's better to do it this way. First of all, he says, if you say the two berachos back-to-back, then then one of those berachos is unnecessary. Second, even if you put the tallis katan and tallis gadol on at different times (and say the two berachos separately), the tallis katan may not be suitable for saying a berachah on anyway: it might be closed too far up the sides, or too small, or you might have slept in it.

See also Dayan Raskin's notes to the Rav's siddur, that another good reason for this practice is because one may put on the tallis katan while his hands are still unclean (before washing negel vasser), or before daybreak. In either of those cases he would have to touch the tzitzis later on (למשמש בציציותיו) and say the berachah "al mitzvas tzitzis," but it is a subject of dispute whether touching them is effective for this purpose.