Multi resolution modifier & retopo help

I just completed sculpting a character using the Multi-Res Modifier and now I want to start to retopologize it. Do I have to apply the Multi-Res Modifier before starting retopo?

In short, no. If you’re going to start doing your retopo work over the sculpt, just leave the multires preview at the lowest appropriate detail level and retopo over that. Applying the sculpt will only irreversibly slow down your viewport.

Thanks much Derek!