How do artists keep track of time?

Special project:)

How do artists keep track of time? 

It's not shift work, 

you probably will not get a bonus working overtime..

so...

What makes an artist committed to what they are doing? 

What makes an artist lose track of time? 

Editted:

When creating a piece filled with patterns.. 

I find it better to limit the number of colours you use.. 

-Spirit Of Life-

8in *10in on 100% cotton paper

Fine Point Pen and Copic Markers