For maximum flexibility the beading is done with thread rather than wire. The bookmarks are not intended to stand up to rough handling, but are intended to be useful for light duty. The doubled thread passes at least twice through each bead; this is strong enough for most purposes, but won't stand up to determined abuse, and sometimes wears out naturally, rubbing on the edges of the natural stones used for some beads.
If a strand of beads breaks in normal use, save the beads and I will repair it for free (you pay only shipping.)
If the ribbon becomes soiled, soak in Woolite, rinse, and hang-dry. Ironing will take out creases.