-w and use strict; can increase your problems, but they will also definately increase your chance of finding hidden problems. I would definately do what it takes to make use strict; happy. -w (or use warnings;) is a harder beast to keep happy and fairly often complains about things that are somewhat reasonable. use strict; and use warnings; can always be overridden for a chunk of wierd code that you have otherwise proven is functioning correctly eg:

use warnings;

my $foo = 1;

{
   no warnings;
   
   my $foo = 2; #normally get a scope warning
}
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use strict; is even better because you can override various subsets of it's checks (eg. no strict 'refs';) - see perldocs for strict and warnings