Distorting type — which includes stretching, squeezing, slanting, etc. in graphic softwares like Illustrator or Photoshop — is often considered a type crime of highest degree. Violating this, either intentionally or unintentionally, will give the impression that you are a designer without any basic knowledge or training.

Why you should never distort type?

Every bit of the letterforms, including proportion and stroke's thickness, is a result of a tedious design process of a typeface designer. By disregarding the work they put into it, you end up creating a bastardized, horrendous version of the typeface itself.

Figure 1. Examples of type distortion | Typeface: GT Eesti

From the examples in Figure 1, you can see that the original type set of GT Eesti typeface — a typeface with unmodulated stroke — has the thickness of the strokes relatively consistent (not mathematically, but optically) throughout the strokes. This is no longer the case when the type set is distorted.

Figure 2. Comparison between Acumin Bold (1), manually stretched Acumin Bold (2) and Acumin Wide Bold (3) | Typeface: Acumin Pro

Type distortion is never an alternative to width variants in type choice. Don't stretch/squeeze type because you need a more extended/condensed version of the font. Find typefaces that suit your need. In the examples of Figure 2, the distorted Acumin typeset (second row) lacks the consistency in stroke weight that the undistorted Bold and Wide Bold variants (first & third row, respectively) have.

Best practice(s)

Simple! Just don't do it. And furthermore, pay attention when you scale type to avoid this to happen.

1. Scale using Font size in Characters settings of the software. It would also be ideal to avoid decimals in your Font size settings.

2. Avoid scaling by click and drag the corners. If you must (ie. already outlined type), always hold shift.

3. Use appropriate Extended (aka Wide) or Condensed variants instead of scaling.

4. Distortions can be applied in kinetic typography, if you know what you are doing, but the static or final state of your type should be undistorted.

It's important to note that what barely noticeable by you, a design student, can be very obvious to the eyes of a trained professional.