We book a lot of trips far in advance so am used to checking for changes after the weekend changes. Seems like if notice in "red" is still there it has shown old and new times which is helpful.
As others have indicated a lot of changes are in minutes and not of any great significance. However, one of the changes a couple of weeks ago on our MCO-RIC trip was significant. DL eliminated our direct flight. We didn't like the change and had no trouble calling and getting the flights we wanted. On the return they had moved up the ATL-MCO segment by two hours and after checking the schedule for that day I saw that they were not flying the usual last flight of the night. We still had a reasonable amount of time to connect so the only loss was our expected dinner at OFS.