Bugs travel in groups. If you see one, look for a second. If you see two close together, look for eight more.
It's never the case that "nothing changed, really!" If you're sure that nothing changed, look again.
The solution will pop out the moment somebody looks over your shoulder. Therefore, arrange for people to look over your shoulder a lot. Better yet, pair program.
The best insurance against bugs sneaking in is a good set of unit tests, run frequently. When you fix a bug, write a new unit test that demonstrates the bug first, then fix it. That way, the bug will stay fixed.
Demos to customers attract bugs. Demo to a friendly audience first.
Remember Rudy's Rutagaba Rule (Weinberg): "Once you eliminate your number one problem, number two gets a promotion." Having another problem is a good thing. It means you still have customers.
Snippets of code should be wrapped in
<code> tags not<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
