Why would a man get his suit made to measure when he can just walk into a shop, try one on and take it away there and then, and probably pay far less? There are a couple of reasons why it makes sense to go made to measure.
Firstly some men have unusual body shapes and no matter how hard the salesman tries to convince you otherwise, the off the peg suit just does not seem to fit right. Some men have extra big thighs, shoulders or another body part and the off the peg suit just will not work. A made to measure suit means the cutter will shape the suit to make allowances for size irregularities.
Another reason a suit might have to be specially constructed is that the person’s trousers size and jacket size do not correspond to the norm. Many men will have a 40 inch chest but might not be the corresponding 34 inch trouser waist. In fact the majority of men will need significant alterations to one part of their suit as the set of trousers and jacket rarely fit perfectly. The made to measure option means that the trousers or jacket does not have to be hacked and butchered to fit the client.
The range of fabrics on offer to someone interested in a made to measure suit are vast. The colours, textures and pattern mixes are far more interesting and varied then the ready made suits in a store. Obviously it is much less of a strain on a retailer to offer hundreds of styles in a small sample cloth cutting then be over stocked with quantities of unsellable suits. The made to measure cloth books will show styles that are no longer available in the shops or that cannot be sourced easily.
Finally it is possible to have unusual features added to your suit that might not be available to the regular store shopper. Internal linings, buttons, lapels and pockets can all be custom made to reflect the specific tastes of the customer.