One of the best ways to prevent cracks is to allow the instrument a stress-free humidification and drying process.
For a new instrument or one that has not been played for a longer period of time, start playing it for 5 minutes at a time.
Remove the barrel, dry the tenon and receiver, put it back together and set it vertically on a stand. Wait for about an hour before repeating the process.
This can be done frequently throughout the day. Contrary to popular belief, it is actually better to play it as often as possible in this way instead of letting it dry all the way out after each session. Increase the playing sessions by a minute every day. After about a month the sessions will already be up to about 35 minutes, by which time the instrument should be ready to play without worry. In this way, the wood will slowly regain moisture and humidity which was reduced in the manufacturing process to increase precision and stability.