The elderly man was very genteel and had lost quite a few pounds in the last year. He came to me with a suit and trousers to cut down to his new size. I successfully cut down the jacket, refitting it from the shoulders down, and it fit him perfectly when I was finished.
Well... those, I found out, can only be taken in a certain amount before the shape is shot. He needed about 5” taken out of the waist and several inches taken in through the length of each leg. No matter what I tried, the pants would pucker in all the wrong places.
The waist could only come in 2” at the most before the back pockets started looking like a unibrow on a hiney.
Conclusion: he needed new trousers.
Because of the shape of the fabric in each leg panel, with all the necessary curves, cutting pants down too drastically is impossible… unless you’re going for a clown look!
Another common scenario is a young lady finds a deal on a prom dress. The only catch is that it is 4 sizes too big, but, hey, anything can be cut down, right?
Yes, anything can be cut down to a degree. It can even be drastic as in the case of making children’s clothes out of aduIt-sized garments. That’s easy. Or a dress can be taken in one, maybe two, sizes before it loses good proportions.
But a dress needing lots of inches taken out of each side will require a MAJOR alteration because the entire bodice will have to be taken apart and re-sewn for a properly-fitting gown. So even though it can be done, be prepared to lose the good deal by paying your seamstress well for having to remake the dress.
The best option is to buy something that fits as nearly as possible.
For wedding and formal dresses with a full bodice, with or without sleeves: the above bust/underarm fit is most critical. All other areas are much easier to adjust (meaning less expensive).
In suits: the neck and shoulders are the most labor-intensive to change. Those need to fit off the rack. Sleeves, hemlines, and vertical shaping are relatively easy to correct.