A custom-made dress involves consultations, designing, pattern-making, cutting, sewing, fitting, more sewing and more fittings. For this reason, it is more expensive than buying one out of a catalogue or from a bridal shop. In order to make it more affordable, some sellers order a dress for brides in one of their standard sizes closest to their body measurements. These dresses are made-to-order rather than custom-made.
Honest sellers advertise these dresses as off-the-shelf or made-to-order. Dishonest sellers, however, tell you they are custom-made but indeed they are made-to-order.
If you pay for a custom-made dress, make sure you get what you pay for. But if you buy a made-to-order or off-the-shelf dress, make sure you control who will alter your dress. Do not simply let your seller does your alterations nor simply trust their referrals without first doing your own due diligence.