By searching a case citation in Google Scholar, then arranging the results by date newest, it is possible to get an idea of the case’s standing. Has it been questioned? Upheld on appeal? Overturned? Cited by many other cases?
Lexis-Nexis, Nexis-Uni, Westlaw and other paid services offer a feature called a citator that checks the standing of cases. Two well-known citators are Shepard's Citations and KeyCite.