"Aft" is the characteristically compressed Scots and older English form of "often," and it is closely associated with Burns's observation that "the best-laid schemes o' mice an' men gang aft agley." The word's brevity suits the aphoristic register of that line and of Scots verse more generally, and it contributes to the sense of a language that says much in few syllables. In poetry "aft" introduces reflection on repetition and habit, the recurring patterns of human and animal life, with a quiet economy that "often" somehow lacks.

Aft is a beautiful archaism that bridges Scots vernacular with the broader literary tradition, appearing in Standard English poetry as "oft" and in Scots as "aft." Burns uses it in tender, reflective passages, and its softness suits elegiac or meditative tones. It shares the same root as English "often" but the Scots compression gives it a slightly more wistful, clipped quality. Students should look for "aft" in contexts of remembered experience or habitual feeling — it frequently introduces nostalgic reflection. Compare with "whiles" (sometimes) and "aye" (always) to understand the range of frequency adverbs available to the Scots poet.