acroyear | why is it?

Why is it that my browser, (Mozilla) Firebird, and my emailer, (Mozilla) Thunderbird, both have this incredible tenacity for running perfectly for months on end, and then start to develop problems with crashing or corrupted files just a couple of days before Mozilla magically releases the next version of each?

Same thing happened when Firebird 0.8 and Thunderbird 0.6 came out -- Firefox started having plug-in problems and Thunderbird corrupted its folder index...

*sigh* -- you'd think opensource would be above such tactics, no?