I am not a Delta flier - but a trip from Tallinn to the U.S. was so much cheaper on Delta, I figure I'd give it a try. I bought the ticket on September 22 - in the (slightly longer than a ) month since I purchased it, the ticket has already been changed FIVE times! Three were small schedule changes, but two were major routing changes. I started out:

Ticket 1 - Outbound TLL-AMS-JFK-CLT Return CLT-BOS-AMS-TLL
Change 1 - small timing change
Change 2 - Outbound TLL-AMS-JFK-CLT Return CLT-ATL-AMS-TLL
Change 3 and 4 - timing changes
Change 5 - Outbound TLL-AMS-ATL-CLT Return CLT-ATL-AMS-TLL

I am not traveling until January - how many more schedule/routing changes should I expect?

TLL-AMS-TLL is on one ticket on Air Baltic and has not changed.