(sloppily made muslin for a dress)
It has been awhile since I wrote one of these "Do I really need to..?" posts but recent muslin making has this topic on my mind.
A muslin (or toile as some call it) is essentially a trial version of a garment using cheap fabric. You make a muslin to test a pattern's fit and avoid making big adjustments to a garment made from your fancy fashion fabric.
Any adjustments made during the muslin process are transferred back to your pattern so you can easily apply them to your final garment.
Most people (myself included) would rather not have to make a muslin because of the extra time dedicated to sewing something you don't intend to wear. Sometimes it is worth the trouble and other times you can get away without one.
When deciding whether to sew a muslin or not, consider these questions:
Does the fashion fabric cost more than $XX? (X being whatever number you think is expensive enough to make you nervous while cutting it). For me that might be anywhere between $5 and $10 depending on how much fabric I am using. If it is expensive, make the muslin. How sad would you be if you made an unfixable fitting mistake on your $25/yd fabric?
Have you sewn this pattern before? If yes, you probably already know the pattern's quirks and issues and probably don't need to make a muslin.
Is it a difficult design? If yes, make the muslin. You don't want to mess up with your good fabric.
Is the pattern design very fitted with lots of curves and darts? If yes, make the muslin, especially if you know you have adjustments you need to make with almost every pattern - full bust, swayback, short torso, etc. If the pattern is a simple gathered skirt for example and the only important measurement is the waist, then you can probably forgo the muslin.
Are you sewing with a fabric you've never used before or is difficult to work with? Make the muslin, it will ease frustration when you make the final garment. However, when sewing the muslin try to use a similar weight and drape of fabric as your fashion fabric. It won't do you any good to make a fitted muslin in quilting cotton when your fashion fabric is a silk charmuse. Your muslin and final garment won't look the same.
Is the pattern made by a company whose designs consistently fit you well (so you know you won't have to make many changes to patterns printed from that company)? In this case you may be able to get away with not making a muslin but refer to the questions above before you take the plunge sans muslin.
(muslin and final shirt. changes made from muslin to final: lengthened hem and sleeves, made armhole larger)
Just because you sew a muslin doesn't mean you double your entire sewing time. When sewing a muslin you don't have to finish seams or hems, sew in linings or facings, add zippers or buttons and generally you may not even have to sew in sleeves or cuffs.
Another bonus is that once you sew a muslin, the second time you sew the pattern it is a breeze because you already know how to put all the pieces together!
You could even get away with only sewing a partial muslin. If only the bodice of a dress needs precise fitting and the skirt is loose you can just sew the bodice like I did in the muslin above.
How do you decide whether to sew a muslin?