Originally Posted by MSPeconomist

Yes, availability can change whenever DL decides to release award seats.

By day to day, I mean to check each possible travel date separately rather than just looking at the award calendar and assuming that it's correct.

For three hops, yes you should search for each segment individually. When you find low award space that you might be able to use, write down the dates, flight numbers, and times. Then try to put it together using search by schedule multi city, picking each segment according to the low inventory that you found. If this doesn't work, call DL and feed the exact segments to the agent. If you explain that you couldn't ticket this on delta.dumb, the phone booking fee might be waived. You can also try asking the agent to put the itinerary on hold for you while you complete the purchase on the website.

I hope you're planning on a RT award ticket, three segments in each direction, right?