Thank you for your previous answers, but the results for my tests weren't what I expected.
It works:
For containers, I used LastChanged in Orion.Containers.
The DateTime column from Orion.ContainerStatus returns dates I'm sure nothing was changed in the Groups themselves. Perhpas it's logging changes in Group Members? In any case, I confirmed that LastChanged is the column I was looking for after adding / removing members to a group.
For Application, I've found that LastModified on Orion.APM.Application has what I expect.
It doesn't work
For nodes, I changed the Node Name and a custom property, but I didn't see anything happening in the Orion.Events log or the Orion.Nodes LastSync column.
SELECT EventID, EventTime, NetworkNode, NetObjectID, EventType, Message, Acknowledged, NetObjectType FROM Orion.Events
WHERE NetObjectType = 'N' AND EventTime > '2014-09-08 10:03:00'
NextPoll and NextRediscovery seem to be populated with a newer date when an node is added though, but not when I change something in the node.
Same for interfaces, I've changed the caption, but InterfaceLastChange and LastChange columns remained unchanged.
I'm still not sure how to retrieve the last Components or Volumes update too.
Any ideas? Am I doing something wrong?