The main thing is to be careful with outer clothes, and even with inner clothes it is important to be careful according to a secret and there is a way of the land and the settlement of the mind.
Sources: In the Gm' Shabbat Ez AB, it means that in an inner garment, it is to be careful that it is not torn, but in Shabbat Kid, in the case of a garment that is not clean, there is dirt that needs to be taken care of in an inner garment as well, and there is a rust in an outer garment, and in our case it is similar to what is mentioned there on Obligation of care only in outer clothing, and also what is mentioned there regarding what needs to be done about the inner clothing is the inner clothing that is slightly visible, which is the clothing mentioned in the above-mentioned page that is slightly visible, only that it is not visible over all the clothes like a cloak, and not on an undergarment that is under the clothing that is not It seems to be a general rule, as it is proven there on page ez, (and a main cover that is not full Gach is sometimes considered to cover everything, as we noted in the case of Kalta and Achmal), and from the Gach of the Shinab C. 2 Skag that care should be taken that the inner part does not become the outer part Also on the robe under the clothes, from the continuation of his words in the SKD, we see Demiry Gach in a robe that is made in a way that might look a bit like an ACP from the side or from the bottom, but in my opinion it is not Meiri at all.
And MM 20 in the order of the day (in the chapter on "the order of the day in the middle of his sleep") to also be careful about the inner clothes according to a secret, and there is also in this from the mental health point of view, according to the 27th vows fa aa regarding unclean clothes that are not Good for the health of the mind, and see Shebat Moser Pachad for this matter.
(I wrote the main points here in Am Segulah 13 C. 9, and now it is more revised)
מק"ט התשובה הוא: 2527