Professor Ahmed Ibrahim (Bek), in his book علم أصول الفقه, summarizes scholars opinions about whether the rulings of the Sahaaba أقوال الصحابة are a juristic mandate. He says that some scholars say so because the Sahaaba were closer to the Prophet, peace be upon him, than everybody else and therefore closer to understanding the intent of rulings. He said that the majority, however, disagreed and their reasoning is that the Sahaaba as distinguished as they were, were human and to err is human.
Professor Ibrahim continues saying that other scholars have differentiated between sayings of the Sahaaba which cannot be their opinions from those that can be. He gives an example of that in Aa'isha (RA) saying that a fetus does not stay in the womb more than two years. These scholars said that in such cases, the ruling should be enforced.
Then he mentions what he said was called "silent consensus", namely a ruling of a Sahaabi that went unopposed, such as Umar's ruling, may God have been pleased with him, that the punishment for drunkenness is eighty floggings. Professor Ibrahim mentioned a couple of examples of renowned scholars accepting the rulings of Sahaaba; Abu-Haneefa took Abu-Bakr's ruling in the grandfather with siblings inheritance situation, while As-Shaafii took instead Zayd ibn Thaabit's ruling. Both Abu-Hannefa and Ash-Shafii agreed on Al-Abbaas's ruling in estate over-subscription. Some scholars have included the followers (At-Taabi`oon) as well.
He finishes with his own opinion that the rulings of the Sahaaba constitute a valid tool for deduction, but not a mandatory one, much like in appellate court as they examine cases and give high regard to scholarly opinions on the case before them.
A candle loses nothing by lighting another candle.