Buying your wedding dress is much more than simply grabbing one off-the-rack and expecting to look exactly like what you saw in the magazine. It is important to know your budget and expectation. If you have a reasonable budget, the dress and its fitting are usually not a problem. However, when the budget is relatively tight, early preparation and careful planning are advised.
If you are going to purchase a sample or a floor stock from a boutique, some major alterations would usually be required to give you a normal fit.
If you are going to purchase a second-hand dress, you probably would notice some alterations were done on the dress for the previous bride. The amount of alterations you need would depend on the body shape and size difference between you and the previous bride, as well as the quality of the alterations previously done on the dress. Mistakes or damages previously done by other seamstresses or tailors would often cost you more to alter and fit your body.
If you are going to order a new dress from a boutique or a designer, your alteration cost would depend a lot on the make of the dress; the sophistication of the dress; and the size of the dress.
Beware of underquoting or overquoting by some seamstresses. Major or complicated alterations require high knowledge, experience and skills from a good seamstress who is capable of accurately estimating the time required to alter your dress and hence can provide you with an accurate cost and a pickup date.