While David Bowie was recording 'Low' in Berlin, he apparently took so much coke that he was unable to finish any song, instead spending weeks on a restless, repetitive fiddling that he later referred to as 'punding'.

Be wary of punding.

As a Creative, time is your only resource. And just as stopping too soon is a deadly sin, so is going on too long.

Hence, it's vital to know when something is finished. Unfortunately, as there are an infinite number of ways to write a headline, or crop a photo, there is no 100% foolproof rational method of deciding when a job of work is done, especially when it comes to craft.

All you have to go on is a feeling. The time to stop is when whatever you're working on 'just feels right.' You need to listen for that feeling in your head, nurture it, and pay heed to it.

Perhaps a couple of analogies might help explain what 'it' is:

In his magnificent book "Hey Whipple Squeeze This" Luke Sullivan quotes the poet William Butler Yeats who said the sound a good poem makes when it's finished is like a lid clicking shut on a perfectly made box.

Then there's these lyrics by New Zealand songwriter Don McGlashan, as featured on Cleaver's blog.

Look at the way this gun fits the crook of your arm
To make a thing like that you’d need to know what you were about
You’d need to know where you were going and go there in a straight line
And everything else you’d have to shut right out

Can you see the man who made that?
Can you see him putting it down and standing back?
Can you see the moment when he said, “that’s it, that’s perfect”?
At a time like that you wouldn’t care about your job
Or your mortgage or the fight you had with your wife
‘Cause when a man holds a thing well made there’s connection
There’s completeness when a man holds a thing well made

I don't actually know who Don McGlashan is, but he hit the nail on the head there for anyone whose job involves crafting something.

Tip No.40 - Challenge The Brief
Tip No.39 - Tell The Truth
Tip No.38 - Playing To Lose
Tip No.37 - How To Write Headlines
Tip No.36 - How To Do Direct
Tip No.35 - How To Do Radio
Tip No.34 - How To Do Press
Tip No.33 - How To Do TV
Tip No.32 - How To Do Digital
Tip No.31 - How To Do Posters
Tip No.30 - Look At Weird Shit
Tip No.29 - Presenting To The Client
Tip No.28 - Presenting To The Team
Tip No.27 - Presenting To The Creative Director
Tip No.26 - How To Deal With Rejection
Tip No.25 - Look Creative
Tip No.24 - Don't Be Afraid To Ask
Tip No.23 - Your Idea Has To Be 120%
Tip No.22 - Read Iain's Tips
Tip No.21 - Don't Behave
Tip No.20 - How To Discuss Ideas
Tip No.19 - Read Hugh's Tips
Tip No.18 - How To Get A Job In Advertising Part IV - How To Turn A Placement Into A Job
Tip No.17 - How To Get A Job In Advertising Part III - How To Approach Agencies (re-print of Tip No. 7)
Tip No.16 - How To Get A Job In Advertising Part II - How To Put A Book Together
Tip No. 15 - How To Get A Job In Advertising Part I - FAQ
Tip No. 14 - Make Friends With Traffic
Tip No. 13 - Get Reference
Tip No. 12 - Don't Stop Too Soon
Tip No.11 - Be Very
Tip No.10 - Breaking Up
Tip No.9 - Working Well With Your Partner
Tip No.8 - Finding The Right Partner
Tip No.7 - How To Approach Agencies
Tip No.6 - Never-Seen-Before Footage
Tip No.5 - Dicketts' Finger
Tip No.4 - Two Blokes In The Pub
Tip No.3 - Play Family Fortunes
Tip No.2 - Should You Take A Bad Job?
Tip No.1 - Don't Overpolish