How much null checking is enough?

Question

What are some guidelines for when it is not necessary to check for a null?

A lot of the inherited code I\'ve been working on as of late has null-checks

Answer 1

I'd say it depends a little on your language, but I use Resharper with C# and it basically goes out of it's way to tell me "this reference could be null" in which case I add a check, if it tells me "this will always be true" for "if (null != oMyThing && ....)" then I listen to it an don't test for null.