I have a brown scapular (and I think a green one, too) that I bought years ago. I have not been invested in it and have never worn it, but notice that those who do wear it ALWAYS wear it. I’m interested in the devotion but am not at the point where I’m willing to wear it all the time. If I know that I will not wear it every day, is it all right to still wear the scapular occasionally?
I do not know of any rule that says one must wear a scapular all the time, particularly so when one has not been invested in it. Wear it as often or as occasionally as you like. With private devotions, the Church leaves such decisions to the individual.