|laziness, impatience, and hubris|
After you've gotten fairly comfortable with perl, I strongly recommend you always load the strict module in all your programs.
Why wait until one has become fairly comfortable with potentially bad habbits? When developing in Perl, always:
There is no reason not to. Using strict and warnings will speed up your learning and your development process. Failing to use them will inhibit you considerably.
One might argue that there are situations where strict and warnings might prevent someone from intentionally, and with full understanding of the ramifications, doing something that strict and warnings see as suspect. I submit that in those rare instances, strict and warnings may be temporarily disabled, or directed to accept a particular thingy. But don't throw out the baby with the bathwater. Just disable them in the portions of code that you know and understand why a stricture violation is still ok. I venture to assert that such cases will be few and far between in normal development.
It is a "Good Idea" to reinforce among both novices and experts alike, the use of strict and warnings. Experts will already know its value. Beginners and novices might not. They should be encouraged to use those pragma's from their very first "Hello world!\n";.
"If I had my life to do over again, I'd be a plumber." -- Albert Einstein