Unless you are sanding in intricate places, it should always be backed-up by either a block or the sponge type sandpaper and since a stock has many different curves, doing so by just using the sandpaper is hard and especially with across the grain figure.

On furniture, especially tables, sandpaper is not the way to go near the end, the only way to get a great finish to to use scrapers like stated earlier, but they must be burnished correctly.

David