When lettering in drafting, what should always be used?

In drafting, using guidelines is crucial for achieving uniformity and clarity in lettering. Guidelines help maintain consistent height, alignment, and spacing between letters and words, thereby enhancing the overall legibility of the text. This practice is especially important in technical drawings where precision is vital, such as in architectural or engineering plans.

By employing guidelines, drafters can ensure that the lettering appears neat and professional, which is essential for effective communication of ideas and instructions. Consistent lettering using guidelines also contributes to the aesthetic quality of the drawing, which reflects the drafter's attention to detail and commitment to quality work.

The other choices do not support the best practices for lettering in drafting. Random guidelines could lead to inconsistency and confusion. Not using any guidelines might result in uneven lettering, while restricting guidelines to uppercase letters could undermine overall text coherence. Therefore, the use of guidelines is integral to effective and professional drafting practices.