More info please, there's not one right answer.
I think it depends on the beer style, how big are you making it and how dry do you want it.
Double IPAs need the sugar for dryness to let the hop flavor through a big grain bill whereas barleywines sometimes just needs the sugar because otherwise there'd be wayy too much malt to keep the beer in the drinkable FG range. In my book, that range ends at 1.025 anything above that turns me off, personally.
Looking up some recipes like a pliny clone, a belgian golden strong etc will give more guidance from style to style