I have checked the data base and have found nothing about undoing subdivide. Is this possible?
In edit mode press the U key
any edit step that doesn’t involve seperating to a new object can be undone. Undo is in the edit menu.
But not if you tabbed out of edit mode and added another object.
Like other people said in edit mode press ‘U’ but if your talking more then the average 32 steps later then i’m afriad your outta luck just have to do with the extra verts.
And if you got alot of patients you could merge them all so you go where you started but thats going to take a long time.