Roasting Meat - Covered or Not?

[jkhdsf]

When roasting meat; after the initial browning stage, should a roast be covered or not?
Why or why not?
Are there exceptions to the rule?

[byrd]

It depends:
Your finest beef rib roast => absolutely not
Finishing a smoked pork shoulder => absolutely
A large turkey => covering the breast for a while doesn't hurt

[Delucacheesemonger]

Perfect by Byrd. If you have taken rib roast from oven and are letting it rest a long time, cover with heavy duty Alum foil. It will not mess up the charred crust yet keep it far warmer.