ZBrush, Mudbox, Sculptris, 3DCoat and all the other voxel based tools demands retop as does Marvelous Designer. Unless you plan to copy other persons work you must learn how to retop.  For some reason experienced people like to exacerbate the difficulties for beginners. You know the lingo, "before you can learn you must unlearn", "we must first tear down". I don't know the reason for this but it is bullshit.

I have recently passed this way so I know what I'm talking about. Many people I talked to were quite supercilious but I noticed that they couldn't retop. On the same time I could go to Youtube and see how young people do it incredible fast and with fine quality. So I learned myself to retop just as well as anyone else on youtube. I am not so easily impressed by self-confessed masters.