Pearls and rhinestones on a bag look expensive and are usually not, which is fine. What matters is knowing how they are attached, because that decides whether they stay on.
What a faux pearl actually is
Most decorative pearls on bags are a glass or plastic bead with a coating on the outside that gives the shine. Glass-based ones feel cool to the touch and slightly heavy. Plastic ones feel warm and light.
Neither is a real pearl and neither is trying to be. The relevant difference is the coating: it can wear off at contact points, and once it wears the bead underneath shows through. That is the usual failure, not the bead falling off.
What a rhinestone is
A rhinestone is cut glass or acrylic with a metallic backing that reflects light back through the front, which is what makes it sparkle. Take the backing off and the stone goes dull and gray.
The backing is the part that water and solvent damage. A stone that has gone cloudy has usually lost its backing, not its surface.
Set versus glued, and how to tell
This is the thing worth checking before you buy.
Set means the decoration sits in a claw, a channel, or is sewn through the material. Look at the edge: you will see metal prongs holding the stone, or thread. Set decoration survives normal wear.
Glued means it is sitting on top of the surface in a bed of adhesive. Look from the side: a glued stone sits proud of the surface with a visible ring of dried adhesive around its base. It will come off eventually, and the eventually is usually sooner than you want.
Run a fingernail gently around a stone at the edge of the panel. Set stones do not move. Glued stones flex slightly.
On our pearl quilted crossbody the pearls and stones are set into the quilting and into the buckle rather than glued on top of the surface, which is one of the things we check before bringing a bag in.
Where they come loose
Almost always at contact points: the bottom corners of the bag, the panel that rests against your hip, and anything near the strap hardware where the bag flexes as you walk.
Decoration in the center of a front panel, or up near the top by the closure, is far safer, because nothing rubs against it.
Keeping them on
Do not put a decorated bag down on rough surfaces. Bar tops, concrete ledges and the underside of restaurant tables take stones off faster than anything else.
Keep perfume and hairspray away from the front. Both contain alcohol, alcohol dissolves adhesive, and both strip the coating on a faux pearl. Spray first, then pick up the bag, not the reverse.
Store it so nothing presses on the decorated face. In a stack of bags, a decorated front under weight will shed stones over a few months of storage without ever being worn.
Cleaning without ruining it
Damp cloth, plain water, wrung out until nearly dry. Wipe the undecorated areas normally. Around stones and pearls, dab rather than scrub, and dry immediately.
No alcohol, no wipes with solvent in them, no jewelry dip. Jewelry cleaners are made for metal settings and will take the backing off a rhinestone and the coating off a faux pearl in one soak.
For dust between stones, a dry soft toothbrush or a makeup brush works better than any liquid.
If one comes off anyway
Keep it. Clear jewelry adhesive, the smallest possible amount on the back of the stone, pressed in place and left overnight untouched. Do not use superglue, which fogs the stone and the surface around it. Do not put the bag down on the repaired side for a day.
If a set stone comes out of its claw, that is a different job. The prongs need bending back with a fine tool, and it is worth taking to a jeweler if the bag is worth keeping.
What to expect from a decorative bag
A pearl and crystal bag is an evening object. Treated as one, with reasonable care, it lasts seasons. Treated like a daily workhorse, thrown in a car footwell and set down anywhere, it will look tired inside a few months, and that is true at every price point.