When Is It Useful To Fail?

The saying goes, “I would have rather have tried and failed than to have never tried at all.”  Is this true?  Doesn’t some failure have far too lasting and unwanted consequences?  Still, we would learn or experience very little if we stuck to doing what’s already comfortable to us.  And, trying new things we might fail at for awhile can be enriching and exciting.

So, when is it useful to fail?  What level of failure do you find acceptable?  What are your limits?

Related questions:  How do you define success?  Do we learn more from our successes or failures?  Is it okay to be wrong sometimes?