The question of what the obligation for the scapular wearer is is a somewhat contentious one, IMO. Last summer/fall I was trying to ascertain what precisely the obligation is and I found conflicting information at every turn. To make things more complicated, it seems the Scapular Promise and the so-called Sabbatine Privilege are often conflated.
The Scapular Promise is that the wearer will not go to hell. The Sabbatine Privilege is release from Purgatory on the Saturday after one’s death.
Fr. William Most has a very good article and an explanation why he thinks nothing except wearing it and being enrolled is necessary:
What conditions are required to gain so great a promise? First of all, the vision spoke of this as a privilege for “all Carmelites.” So it is necessary to be in some way affiliated with the Order of Carmel. For most Catholics, this is accomplished through enrollment in the Confraternity of the Scapular.
But is there anything else required? Not a few Catholics -including some who should know better - insist that she should know what the requirements are. That she mentioned nothing other than wearing the Scapular at the time of death. Therefore we must not add anything else.
And this makes sense to me. The story of the Brown Scapular doesn’t mention requirements other than being enrolled and wearing it.
I will note that there is much conflicting information.
Carmelnet.org says:
Code:
The Scapular holds us to live as authentic Christians in line with the teaching of the Gospel, to receive the sacraments, to profess our special devotion to the Blessed Virgin, which should be expressed each day, at least by saying the Hail Mary three times.
To wear the Scapular without also cultivating a Marian devotion would seem to make little sense.
Ultimately, though, I think the greater requirements for the Scapular stem from conflation with the Sabbatine Privilege. Fr. Most is again most illustrative:
There is also a Sabbatine Privilege. The report is that Pope John XXII hada vision of Our Lady on March 3, 1322, in which liberation from purgatory was promised on the first Saturday after death, on three conditions**: 1)Wear the Scapular 2) Observe 6th and 9th commandments according to one’s state in life 3) say the Little Office, or, if illiterate, observance of the fasts of the Church plus abstinence on Wednesdays and Saturdays. The requirement of the Office can be commuted by a priest who has the faculty.
** A daily rosary is a common commutation. Those bound to the large office fulfill the condition by saying it.
The original copy of the bull was lost. This is not too strange in view of the disturbed state of Rome after the sack of 1527. Some other documents of the same Pope are also lost. There was a copy of the bull, given by Pope Clement VII, dated May 15, 1528, but for some reason it was never solemnly issued, and so is technically invalid. The same Pope on August 12, 1530 did issue a transcript, but it promised only special help, not liberation.
So it would seem that the Sabbatine Privilege is what requires the daily rosary. The Sabbatine Privilege is much less well established than the Scapular Promise.
However, I do recommend praying the rosary daily.

It is a beautiful devotion.
As for wearing or not wearing the Scapular-- if one removes the scapular briefly for a legitmate reason, i.e., for a shower, the promises still apply.