[hitsthings]

Pattern 1 you can pass in a logger there or a noop logger and not have any duplication.

[pavel_lishin]

It's not my job to pass a logger to some given class method. Should I pass in a database handle and a DNS resolver, too?

[d--b]

Well, I could do operations for logging that are otherwise not required...

   if(log) { logger.write(computestuff()); }

[meheleventyone]

Depending on language if you have first class functions you could also do:

  logger.write(computestuff);

Or for parameterized functions:

  logger.write(() => computestuff(a, b, c));

Then all that logging policy stuff can live with the logging and doesn't need to be checked explicitly throughout the codebase.

[rini17]

This means to interrupt whatever you're doing and implement the logger and do the associated refactoring.