Does working hard guarantee success? No, I don’t believe it does. But I do believe it is a necessary ingredient for success. How do we learn to work hard? Is it taught, instilled in us by example or drilled into us? 
I look back upon many aspects of my life as I try to teach my children lessons. I think one of the reasons I work hard is that it is gratifying. Especially in my current work. I can see the results of my hard work. In some jobs that I have had that was not always the case. I could work hard, but feel like I was spinning my wheels and not really accomplishing anything. 
I am sure a work ethic was instilled in me by my parents. It started with simple chores. It was also exhibited by their own hard work, at their jobs, parenting, maintaining a home, helping neighbors and family. For my own kids, we have expected them to work hard, but try to develop the desire within them – not demand it. 
And I have seen my kids work hard. My son spends hours practicing piano daily. It is unimaginable to me. But he knows he has to work hard to achieve his goals. He looks back on his high school years and wishes he had worked harder. That is the wisdom that age gives us. He insists that he learned about hard work by watching his parents work so hard. That is a wonderful compliment to receive from your son.
My kids have worked diligently at their schoolwork. I know, however, that that does not always guarantee “success”. They have experienced rejection from colleges, jobs, and scholarships. Colleges see what is on a paper. They might have some idea of work ethic based on grades. But they have no way of knowing whether that student is going to work hard in college. I saw it myself back in the day. Kids who skimmed the surface in high school had no idea of how to handle the work load in college. Or as my kids have so wisely said, they should give scholarships to students after they have been in college based on their work ethic and accomplishments during college – not high school.  They have seen students on full rides not make good use of the gift that was given to them.
Perhaps that is the conundrum. When we are handed things, we no longer work hard for it. I recently read “David and Goliath” and “Outliers” by Malcolm Gladwell. Both are fascinating books on the concept of success. One interesting example is the work ethic or a young boy who started out poor, worked hard and achieved great financial success. The same ethic was very difficult to instill in his children, who had everything. 
I believe there might have been a time when you could get a job, work hard and retire comfortably. But our current economic environment and corporate climate does not necessarily reward hard work and loyalty. I can tell you that my husband, one of the hardest-working persons I know, was not rewarded in his job of 24 years for only taking 2 sick days. 
No, hard work does not guarantee success. The cynic in me sometimes wonders why bother working hard? Perhaps we should just “dance through life” as Fiyero sings in “Wicked:”

The trouble with schools is

They always try to teach the wrong lesson

Believe me, I’ve been kicked out

Of enough of them to know

They want you to become less callow

Less shallow

But I say: Why invite stress in?

Stop studying strife

And learn to live “the unexamined life”

Dancing through life

Skimming the surface

Gliding where turf is smooth

Life’s more painless

For the brainless

Why think too hard

When it’s so soothing?

Dancing through life

No need to tough it

When you can slough it off as I do

Nothing matters

But knowing nothing matters

It’s just life

So keep dancing through…

Dancing through life

Swaying and sweeping

And always keeping cool

Life is fraught less

When you’re thoughtless

Those who don’t try

Never look foolish

Dancing through life

Mindless and careless

Make sure you’re where less

Trouble in life

Woes are fleeting

Blows are glancing

When you’re dancing

Through life…
In some cases, it may be valuable to notch it back a bit. For some of us, who are perfectionists, we can add a lot of stress to our lives by working until we think we have it “right”. I have even advised some in my family to dial it back to the point where you can “get by.” Seems like crazy advice, but there is such a thing as working too hard – when it affects your health. And there is a point that working extra hard does not get you extra reward. You have to know and accept that sometimes “good enough” is ok.  
I want my kids to work hard….especially at what they love to do. But I also want them to know that in all things they should work hard. That means even when cleaning the bathroom. I don’t love it, but it’s a job that has to be done and should be done well. My daughters helped me get started on the studio cleanup. One tackled the cabinet, clearing out junk, reorganizing and making new labels while the other tackled the drawers. I circled through the entire room, dusting, vacuuming, and reorganizing. Working hard on this project felt great. I love it when we can feel the rewards of our hard work.
I suppose that the rewards of hard work should be felt on the inside. It may be recognized by others, but that should not be our primary motivation.