This is the second time this week that I encountered a annoying bug, introduced just by a small change in the code. Just when you think you can get away with minor changes without testing, you are in for a surprise.
The most common sense thing you can do is to test your code even for small changes; whether you are testing it yourself or sending it to the testing team. Seems simple, but how many times have you really done that. Its not that we are stupid, rather software was never so simple. Maybe we are careless sometimes. The moral is plain – treat even small changes important, and move it through a test before committing it to a version control.