After reading the following teaching in DN2, I realized any means of beautification is forbidden for a monk/nun as a means of sense restraint:
"Whereas some brahmans and contemplatives, living off food given in faith, are addicted to scents, cosmetics, and means of beautification such as these — rubbing powders into the body, massaging with oils, bathing in perfumed water, kneading the limbs, using mirrors, ointments, garlands, scents, creams, face-powders, mascara, bracelets, head-bands, decorated walking sticks, ornamented water-bottles, swords, fancy sunshades, decorated sandals, turbans, gems, yak-tail whisks, long-fringed white robes — he abstains from using scents, cosmetics, and means of beautification such as these. This, too, is part of his virtue."
Or probably it's not only for a monk/nun, but also for lay practitioners who hold the 8 precepts (e.g. on Uposatha days)? Should the above-listed things be all included in the 7th precept? I thought the use of mirror and creams are not only for beautification, but also for social appropriateness and health. Probably it's up to one's intention?
I also have a little trouble with the 8th precept: "He abstains from high and luxurious beds and seats" and the practice of sleeping on the floor. I guess the ancient Indian high beds and seats must be very luxurious. That's why the Buddha associated these two together. From the perspective of health and safety, it would be better to sleep on a bed with certain height instead of on the floor. I suppose it's again up to one's intention?
A little more trouble with the 6th precept: "He eats only once a day, refraining from the evening meal and from food at the wrong time of day (after noon?)." I think this teaching is for monastics or the lay in retreats, not for working lay practitioners. Otherwise we'll have to eat a lot during that one meal in order to have enough energy to work for the rest of the day, which might not be so healthy. Refraining from food after noon could be impractical for some working lay practitioners who might have to work before and during the noon hours and can only have lunch in the afternoon.
Well, at the end it's a matter of purifying the mind. I guess some formats might not be so important, as long as we have right intention and have no attachments to sensual indulgence? But these are the Buddha's requirements, the precepts, our sacred vows ...