The sketch deserves to stay.
Some of the best decisions appear before the finishing touches.
#Keep the first impulse
An uneven line can hold energy that disappears in an overly corrected version. Before erasing it, make a copy or move the study to another layer. You gain room to experiment without losing what you liked at the start.
#Choose what needs precision
Not every part of a drawing needs equal attention. The silhouette might need clarity while the contour stays loose. In a childlike asteroid drawing, small differences between craters preserve character. Use polish to guide the eye instead of correcting everything out of habit.
#Keep the process in the project
In Zyggs, sketch and guide layers remain in the project file but are excluded from export. Keep studies, directions and alternatives there. The editable file preserves decisions a finished image cannot show. Save the project after exporting, too.
#Exercise
Redraw a simple object in three minutes. Then choose only three things to improve. Keep the rest and compare it with the first version.